NZ736509B2 - Apparatus and process for packaging a product - Google Patents
Apparatus and process for packaging a product Download PDFInfo
- Publication number
- NZ736509B2 NZ736509B2 NZ736509A NZ73650916A NZ736509B2 NZ 736509 B2 NZ736509 B2 NZ 736509B2 NZ 736509 A NZ736509 A NZ 736509A NZ 73650916 A NZ73650916 A NZ 73650916A NZ 736509 B2 NZ736509 B2 NZ 736509B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- film
- packaging
- apertures
- gas
- tray
- Prior art date
Links
- 238000004806 packaging method and process Methods 0.000 title claims abstract description 293
- 238000000034 method Methods 0.000 title claims abstract description 60
- 239000007924 injection Substances 0.000 claims abstract description 37
- 238000002347 injection Methods 0.000 claims abstract description 37
- 238000004320 controlled atmosphere Methods 0.000 claims abstract description 33
- 239000007789 gas Substances 0.000 claims description 163
- 238000010438 heat treatment Methods 0.000 claims description 74
- 210000000214 Mouth Anatomy 0.000 claims description 51
- 239000000203 mixture Substances 0.000 claims description 45
- 238000005520 cutting process Methods 0.000 claims description 42
- 230000002093 peripheral Effects 0.000 claims description 33
- 230000000875 corresponding Effects 0.000 claims description 27
- 239000012298 atmosphere Substances 0.000 claims description 25
- 238000007789 sealing Methods 0.000 claims description 19
- 230000015572 biosynthetic process Effects 0.000 claims description 15
- 238000005755 formation reaction Methods 0.000 claims description 15
- 239000012530 fluid Substances 0.000 claims description 14
- 229910052760 oxygen Inorganic materials 0.000 claims description 14
- 230000000284 resting Effects 0.000 claims description 12
- 238000004891 communication Methods 0.000 claims description 8
- 230000003213 activating Effects 0.000 abstract description 4
- 239000010408 film Substances 0.000 description 282
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- 239000005977 Ethylene Substances 0.000 description 23
- 239000004952 Polyamide Substances 0.000 description 23
- VGGSQFUCUMXWEO-UHFFFAOYSA-N ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 23
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- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 10
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- WNLRTRBMVRJNCN-UHFFFAOYSA-N Adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 6
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 description 6
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- 238000009466 skin packaging Methods 0.000 description 5
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- DNIAPMSPPWPWGF-UHFFFAOYSA-N propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000002356 single layer Substances 0.000 description 4
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 3
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- QQVIHTHCMHWDBS-UHFFFAOYSA-N Isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 3
- YIMQCDZDWXUDCA-UHFFFAOYSA-N [4-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1CCC(CO)CC1 YIMQCDZDWXUDCA-UHFFFAOYSA-N 0.000 description 3
- 239000001361 adipic acid Substances 0.000 description 3
- 235000011037 adipic acid Nutrition 0.000 description 3
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- 235000013351 cheese Nutrition 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
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- 239000006260 foam Substances 0.000 description 3
- 238000011068 load Methods 0.000 description 3
- 229920001684 low density polyethylene Polymers 0.000 description 3
- 239000004702 low-density polyethylene Substances 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- 239000002985 plastic film Substances 0.000 description 3
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000004800 polyvinyl chloride Substances 0.000 description 3
- 244000144977 poultry Species 0.000 description 3
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- 239000000243 solution Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- 229920001169 thermoplastic Polymers 0.000 description 3
- 239000004416 thermosoftening plastic Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- ZNAMMSOYKPMPGC-HTOAHKCRSA-N (2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-(2-phenylethylsulfanyl)oxane-3,4,5-triol Chemical compound O[C@@H]1[C@@H](O)[C@@H](O)[C@@H](CO)O[C@H]1SCCC1=CC=CC=C1 ZNAMMSOYKPMPGC-HTOAHKCRSA-N 0.000 description 2
- ALQSHHUCVQOPAS-UHFFFAOYSA-N 1,5-Pentanediol Chemical compound OCCCCCO ALQSHHUCVQOPAS-UHFFFAOYSA-N 0.000 description 2
- 229940043375 1,5-pentanediol Drugs 0.000 description 2
- XXMIOPMDWAUFGU-UHFFFAOYSA-N 1,6-Hexanediol Chemical compound OCCCCCCO XXMIOPMDWAUFGU-UHFFFAOYSA-N 0.000 description 2
- 102100017978 MNT Human genes 0.000 description 2
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- XNGIFLGASWRNHJ-UHFFFAOYSA-N Phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene (PE) Substances 0.000 description 2
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N Triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 description 2
- 239000004708 Very-low-density polyethylene Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000000844 anti-bacterial Effects 0.000 description 2
- 230000000111 anti-oxidant Effects 0.000 description 2
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- 239000002216 antistatic agent Substances 0.000 description 2
- 125000003118 aryl group Chemical group 0.000 description 2
- 239000003899 bactericide agent Substances 0.000 description 2
- 235000015173 baked goods and baking mixes Nutrition 0.000 description 2
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- 238000009833 condensation Methods 0.000 description 2
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- VKONPUDBRVKQLM-UHFFFAOYSA-N cyclohexane-1,4-diol Chemical compound OC1CCC(O)CC1 VKONPUDBRVKQLM-UHFFFAOYSA-N 0.000 description 2
- 230000003247 decreasing Effects 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- 239000003623 enhancer Substances 0.000 description 2
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- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000009448 modified atmosphere packaging Methods 0.000 description 2
- WPUMVKJOWWJPRK-UHFFFAOYSA-N naphthalene-2,7-dicarboxylic acid Chemical compound C1=CC(C(O)=O)=CC2=CC(C(=O)O)=CC=C21 WPUMVKJOWWJPRK-UHFFFAOYSA-N 0.000 description 2
- 235000015927 pasta Nutrition 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 229920000747 poly(lactic acid) polymer Polymers 0.000 description 2
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- 239000000454 talc Substances 0.000 description 2
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- 229920001862 ultra low molecular weight polyethylene Polymers 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 238000009460 vacuum skin packaging Methods 0.000 description 2
- 229920001866 very low density polyethylene Polymers 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 239000001993 wax Substances 0.000 description 2
- LGXVIGDEPROXKC-UHFFFAOYSA-N 1,1-Dichloroethene Chemical compound ClC(Cl)=C LGXVIGDEPROXKC-UHFFFAOYSA-N 0.000 description 1
- PDKAXHLOFWCWIH-UHFFFAOYSA-N 1,1-dichlorobuta-1,3-diene Chemical compound ClC(Cl)=CC=C PDKAXHLOFWCWIH-UHFFFAOYSA-N 0.000 description 1
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-Hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 1
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- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-Methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 1
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- 235000006770 Malva sylvestris Nutrition 0.000 description 1
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- 150000007513 acids Chemical class 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid Chemical compound OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
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- 125000005250 alkyl acrylate group Chemical group 0.000 description 1
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- 239000011248 coating agent Substances 0.000 description 1
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- 125000004122 cyclic group Chemical group 0.000 description 1
- QYQADNCHXSEGJT-UHFFFAOYSA-N cyclohexane-1,1-dicarboxylate;hydron Chemical class OC(=O)C1(C(O)=O)CCCCC1 QYQADNCHXSEGJT-UHFFFAOYSA-N 0.000 description 1
- PXGZQGDTEZPERC-UHFFFAOYSA-N cyclohexane-1,4-dicarboxylic acid Chemical compound OC(=O)C1CCC(C(O)=O)CC1 PXGZQGDTEZPERC-UHFFFAOYSA-N 0.000 description 1
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- 238000002845 discoloration Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- QHZOMAXECYYXGP-UHFFFAOYSA-N ethene;prop-2-enoic acid Chemical compound C=C.OC(=O)C=C QHZOMAXECYYXGP-UHFFFAOYSA-N 0.000 description 1
- 239000005042 ethylene-ethyl acrylate Substances 0.000 description 1
- 239000005043 ethylene-methyl acrylate Substances 0.000 description 1
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- 235000013410 fast food Nutrition 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 235000019688 fish Nutrition 0.000 description 1
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- 238000001746 injection moulding Methods 0.000 description 1
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- 239000012212 insulator Substances 0.000 description 1
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- 150000002500 ions Chemical class 0.000 description 1
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- 238000002844 melting Methods 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
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- 229920005629 polypropylene homopolymer Polymers 0.000 description 1
- 235000013594 poultry meat Nutrition 0.000 description 1
- 235000020991 processed meat Nutrition 0.000 description 1
- 235000020989 red meat Nutrition 0.000 description 1
- 230000002829 reduced Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000007127 saponification reaction Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 230000001340 slower Effects 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
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- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical group [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
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Abstract
process and apparatus (1) for packaging a product (P) arranged on a tray (4) is disclosed. The apparatus comprises a packaging assembly (8) configured for tightly fixing one or more film sheets to one or more trays. The packaging assembly includes a lower tool (22) defining a prefixed number of seats (23) for receiving the trays and an upper tool (21) facing the lower tool and cooperating with the upper tool to define a packaging chamber (24). The packaging assembly (8) is configured to operate at least in a first operating condition, where said packaging chamber (24) is open, and in a second operating condition, where said packaging chamber (24) is hermetically closed. First injection apertures (90) are positioned in corner regions of the seat and are configured to inject streams of gas in a direction substantially parallel to and above the flange (4c) of a tray (4) positioned in said seat. The process includes the step of activating injection of a plurality of streams of gas through said first apertures (90) in order to form a controlled atmosphere inside the tray before closing the tray with the film. The apparatus and/or process aim to efficiently and accurately position a film and/or a tray in a packaging process and to avoid or at least reduce some disadvantages associated with packaging such as film and/or tray misplacement and/or uncontrolled deformation. ats (23) for receiving the trays and an upper tool (21) facing the lower tool and cooperating with the upper tool to define a packaging chamber (24). The packaging assembly (8) is configured to operate at least in a first operating condition, where said packaging chamber (24) is open, and in a second operating condition, where said packaging chamber (24) is hermetically closed. First injection apertures (90) are positioned in corner regions of the seat and are configured to inject streams of gas in a direction substantially parallel to and above the flange (4c) of a tray (4) positioned in said seat. The process includes the step of activating injection of a plurality of streams of gas through said first apertures (90) in order to form a controlled atmosphere inside the tray before closing the tray with the film. The apparatus and/or process aim to efficiently and accurately position a film and/or a tray in a packaging process and to avoid or at least reduce some disadvantages associated with packaging such as film and/or tray misplacement and/or uncontrolled deformation.
Description
TITLE
Apparatus and process for packaging a product.
DESCRIPTION
Technical field
The present invention relates to an apparatus and to a process for packaging a product. In accordance with other
aspects, the invention relates to an apparatus and process for packaging a product under a controlled atmosphere.
Background art
Containers are commonly used for the packaging of food and for a wide variety of other items wherein a lid is bonded
to the container e.g. by the application of heat. The containers and lids can be made of a number of materials, for
example plastic, metal, or combinations thereof, whereas the lid is typically supplied in form of a continuous film and
subsequently cut into a suitable shape either before or after bonding. In some examples, a plastic lid is pre-cut into a
suitable shape and subsequently heat bonded onto a plastic tray.
In order to package products, in particular food products, vacuum packaging has been developed and refined in the
past. Vacuum skin packaging is basically a thermoforming process. In particular, the product is typically placed on a
rigid or semi-rigid support (such as a tray, a bowl, or a cup). The support with the product placed thereon is put in a
vacuum chamber, where a film of thermoplastic material, held by a local vacuum in a position above the product placed
on the support, is heated to make it more yielding. The space between the support and the film is evacuated. The film
is then sealed at the perimeter of the tray to fix its position relative to the tray and the local vacuum above the film is
shut off, releasing the film. When the vacuum inside the chamber is decreased, the vacuum inside the tray causes the
film to drape down all around the product and seal to the surface of the support not covered by the product, thus
forming a tight skin around the product and on the support. In the known apparatus vacuum is formed by vacuum
pumps withdrawing air via channels connected to the vacuum chamber: although the tray and the film portion located
in the vacuum chamber are held in place by appropriate holders the suction caused by vacuum may cause gas streams
determining undesired dislocation of the trays and/or of film portions which in the end may compromise quality of the
heat bonding. Also, gas streams caused by vacuum formation in the vacuum chamber may cause uncontrolled
deformation of film portions and/or of the tray flange with consequent possible reduction of the bonding quality.
Another packaging methodology is referred to as tray lidding. In tray lidding processes, a lid is positioned on a film
holder above a tray: then either normal atmosphere is left in the tray or – more typically when it comes to packaging
food products - injection of a gas of controlled composition takes place. Afterwards the lid is heat bonded to the tray:
in detail, a sealing tool is configured to act upon the portions of the film extending beyond the film holder in order to
seal the film to the tray. The portions of the film extending beyond the film holder are prone to deformation due to a
number of packaging process related factors: heat emitted from the sealing tool or other components, turbulence of
gas or air created upon evacuation and/or upon creation of the inert atmosphere, mechanical movement of components
of the packaging tool, mechanical resistance and/or rigidity of the material at certain process related temperatures, etc.
When such deformation occurs, the quality of the seal can be compromised, possibly leading to a seal of mediocre
quality or a defective seal. Also, gas flows during the packaging process may cause dislocation from proper position
and/or deformation of the tray flange, thus leading to a sealing between film and tray flange.
Furthermore, in applications where a controlled atmosphere has to be created in the package, it may be problematic
to efficiently and quickly evacuate air and generate the proper modified atmosphere. A solution which has been
proposed in the past in order to solve this problem is described in EP 2641835.This reference shows a packaging
machine wherein a tool system hosts a tray. Gas supply apertures are positioned in a tool of the tool system and are
configured to generate a gas stream which is substantially parallel to the top flange of the tray. The gas supply apertures
and the gas evacuation apertures are positioned at respective opposed ends of a common side of the tool: this
particular relative position of the gas injection and of the gas evacuation apertures is claimed to improve formation of
a controlled atmosphere in the tray.
Therefore, it is an object of the invention
• to provide a process and an apparatus, which can efficiently and accurately position a film and/or a tray in a
packaging process, and/or
• to provide an apparatus and a process able to avoid or at least reduce film and/or tray misplacement during
a packaging process, and/or
• to provide a process and an apparatus suitable for packaging of products under a controlled atmosphere and
capable of efficient gas injection and/or gas removal and therefore efficient control of gas composition inside
a package during the packaging process, and/or
• to provide a process and an apparatus configured such as to avoid uncontrolled deformation of the film and/or
tray during a packaging process, and/or
• to at least provide the public with a useful choice.
In the description in this specification reference may be made to subject matter that is not within the scope of the claims
of the current application. That subject matter should be readily identifiable by a person skilled in the art and may assist
in putting into practice the invention as defined in the claims of this application.
In this specification where reference has been made to patent specifications, other external documents, or other
sources of information, this is generally for the purpose of providing a context for discussing the features of the
invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an
admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the
common general knowledge in the art.
Summary of the invention
One or more of the objects specified above are substantially achieved by a process and by an apparatus according to
any one of the appended claims. Described aspects and aspects of the invention are disclosed below.
In a first aspect the present invention provides an apparatus (1) for packaging a product (P) arranged on a tray (4),
said apparatus (1) comprising a packaging assembly (8) configured for tightly fixing a film (10; 18) to one or more trays
(4), the packaging assembly (8) including a prefixed number of seats (23) configured for receiving said one or more
trays (4), wherein:
- each of said seats (23) presents a mouth (23b) peripherally delimited by an abutment surface (23a), each of
said seats (23) being configured to receive at least one respective tray (4) with a flange (4c) of each tray (4) resting on
the abutment surface (23a) of the respective seat (23), and
- the packaging assembly (8) defines – in correspondence of each of said seats (23) - a number of first apertures
(90) configured to inject gas towards the inside of the respective seat, wherein each of said first apertures is positioned
in correspondence of the mouth (23b) of the respective seat (23) and extends above said abutment surface (23a);
wherein the packaging assembly (8) includes, for each of said seats (23), a number of second apertures (93) located
on a side of the seat (23) opposite with respect to the first aperture(s) (90);
wherein the packaging assembly (8) further comprises:
- a lower tool (22) defining the prefixed number of seats (23) and hosting a number of first conduits (91), wherein
the first conduits present terminal edges (92) delimiting said first apertures (90) such that each of said first apertures
(90) presents at least a major portion extending above the abutment surface (23a) of the respective seat (23);
- an upper tool (21) facing the lower tool (22), at least the upper and lower tools (21; 22) cooperating to define
a packaging chamber (24); and
- a control unit (100) connected to the packaging assembly (8) and configured for commanding the packaging
assembly (8) to pass from a first operating condition, where said packaging chamber (24) is open to receive the film
(10; 18), and a second operating condition, where said packaging chamber (24) is closed;
wherein the lower tool (22) first conduits (91) have an end, terminating in said terminal edges defining said first
apertures (90), and an opposite end, in fluid communication with a gas supply circuit (94);
wherein the lower tool (22) comprises a number of second conduits (95) having an end, terminating in said second
apertures (93), and an opposite end, in fluid communication with a gas evacuation circuit (96), and
wherein each of said first apertures (90) is positioned in correspondence of corner regions of the mouth (23b) of the
respective seat (23).
In a second aspect the present invention provides a process of packaging a product (P) arranged on a tray (4) using
the apparatus (1) according to any one of the preceding claims, the process comprising the following steps:
- moving a film (10; 18) into the packaging chamber (24) of said packaging assembly (8),
- moving a tray (4) into the packaging chamber (24) and below said upper tool (21),
- causing the packaging assembly (8) to pass from the first to the second operating condition, with the film held
above a number of said trays,
- injecting gas through said first apertures (90);
- heat sealing the film sheet (18) to the tray (4).
A 1 described aspect concerns an apparatus (1) for packaging a product (P) arranged on a tray (4), said apparatus
(1) comprising a packaging assembly (8) configured for tightly fixing a film (10; 18) to one or more trays (4), the
packaging assembly (8) including a prefixed number of seats (23) configured for receiving said one or more trays (4),
wherein:
- each of said seats (23) presents a mouth (23b) peripherally delimited by an abutment surface (23a), each of
said seats (23) being configured to receive at least one respective tray (4) with a flange or top flange (4c) of
each tray (4) resting on the abutment surface (23a) of the respective seat (23), and
- the packaging assembly (8) defines – in correspondence of each of said seats (23) - a number of first
apertures (90) configured to inject gas towards the inside of the respective seat, wherein each of said first
apertures is positioned in correspondence of a corner region (23c) of the mouth (23b) of the respective seat
(23) and extends above said abutment surface (23a).
For example the tray (4) may have a base wall (4a), a side wall (4b) and a top flange (4c) radially emerging from the
side wall.
nd st
In a 2 described aspect according to the 1 described aspect the packaging assembly comprises a lower tool (22)
defining the prefixed number of seats (23) and hosting a number of first conduits (91), wherein the first conduits present
terminal edges (92a) delimiting said first apertures (90) such that each of said first apertures (90) entirely extends
above the abutment surface (23a) of the respective seat (23). The packaging assembly also has an upper tool (21)
which faces the lower tool (22), wherein at least the upper and lower tools (21; 22) cooperate to define a packaging
chamber (24).
In a 3 described aspect according to any one of the preceding described aspects the apparatus has ejectors (92)
(which may be formed by the terminal portions of first conduits (91)) positioned and configured to eject a gas stream
tangential and parallel to the abutment surface (23b) and therefore tangential and parallel with respect to a tray flange
(4c) resting above the abutment surface (23b) of a seat (23). In accordance with an auxiliary described aspect the
ejectors (92) entirely extend above and parallel to the abutment surface (23b) and present a fluid passage area with
axis parallel to the abutment surface (23b) and therefore tangential and parallel with respect to a tray flange (4c) resting
above the abutment surface (23b) of a seat (23). The first apertures (90) are formed by the passage areas delimited
by the terminal edges (92a) of said ejectors (92) and lie on a surface generally transverse – optionally perpendicular –
to a first ideal plane (L1) passing through the abutment surface (23b). The first apertures (90) may be located and may
entirely extend above the abutment surface (23a). For instance, each of said first apertures (90) may be positioned in
correspondence of corner regions of the mouth (23b) of the respective seat (23).
In a 4 described aspect according to any one of the preceding described aspects the upper tool comprises an insert
(36) acting as film holder having a respective bottom surface (37) configured for holding the film (10; 18) above the
respective seats: the insert carrying film holding means which may include holes connected to a vacuum source, an
adhesive layers, mechanical holders or other.
In a 5 described aspect according to any one of the preceding two described aspects the apparatus includes a control
unit (100) connected to the packaging assembly (8) and configured for commanding the packaging assembly (8) to
pass from a first operating condition, where said packaging chamber (24) is open to receive the film (10; 18), and a
second operating condition, where said packaging chamber (24) is closed.
In a 6 described aspect according to anyone of the preceding three described aspects the packaging chamber when
in the closed condition is hermetically closed, meaning that the chamber is fluidly isolated from the environment external
to the chamber itself other than for conduits leading to a vacuum arrangement and/or a controlled atmosphere
arrangement as discussed below..
In a 7 described aspect according to anyone of the preceding described aspects each seat (23) has the respective
mouth (23b) of polygonal, preferably rectangular, shape and wherein said first apertures (90) include at least one first
aperture (90) at a first corner region (23c) and at least one first aperture (90) at a second corner region (23c) adjacent
to the first corner region of the mouth (23b).
In a 8 described aspect according to anyone of the preceding described aspects the packaging assembly (8) includes,
for each of said seats (23), a number of second apertures (93) located on a side of the seat (23) opposite with respect
to the first aperture(s) (90).
In a 9 described aspect according to the preceding described aspect the second apertures are positioned and entirely
extend either above or below the abutment surface (23a) of the respective seat.
In a 10 described aspect according to the any one of the preceding two described aspects the second apertures are
located below the level of the abutment surface and are positioned in correspondence of a central region of the side of
the seat (23) opposite to the corner regions (23c) where the first apertures are located.
In a 11 described aspect according to anyone of the preceding described aspects the lower tool (22) comprises a
number of first conduits (91) having an end, terminating in said terminal edges defining said first apertures (90), and
an opposite end, in fluid communication with a gas supply circuit (94).
In a 12 described aspect according to anyone of the preceding described aspects a number of second conduits (95)
having an end, terminating in said second apertures (93), and an opposite end, in fluid communication with a gas
evacuation circuit (96).
In a 13 described aspect according to anyone of the preceding two described aspects the gas supply circuit (94) is
connected with the control unit (100) which is further configured to command the supply circuit to supply gas having a
controlled composition to the first conduits.
In a 14 described aspect according to anyone of the preceding three described aspects the gas evacuation circuit
(94) is connected with the control unit (100) which is further configured command the evacuation circuit to withdraw
gas from the second conduits.
In a 15 described aspect according to anyone of the preceding described aspects each of said first apertures (90)
has the shape of an elongated slit having a width (w) greater than a height (h), wherein the width is measured parallel
to an horizontal plane and is at least two times greater than the height, which is measured parallel to a vertical plane.
th st th
In a 16 described aspect according to anyone of the preceding described aspects from the 1 to the 14 said first
apertures present at each corner region (23c) a plurality of horizontally aligned, optionally circular, apertures.
In a 17 described aspect according to anyone of the preceding described aspects the abutment surface (23a) of each
seat (23) lies on a first ideal plan (L1) and wherein the upper tool (21) includes insert (36), with the bottom surface (37)
of the insert being designed to contact the film and developing on a second ideal plane (L2) parallel to the first ideal
plane (L1), and wherein terminal edges of the first conduits leading to said first apertures position the first apertures
(90) between the first ideal plane and the second ideal plane.
In an 18 described aspect according to the preceding described aspect the first apertures (90) have a shape elongated
in a direction parallel to said first and second ideal planes and/or comprise a plurality of apertures aligned along said
first and second ideal planes.
In a 19 described aspect according to any one of the preceding two described aspects, the insert is film holder.
In a 20 described aspect according to anyone of the preceding described aspects the abutment surface (23a) of each
seat (23) extends about the mouth (23b) of the respective seat and forms a corresponding radial band designed for
receiving the flange (4c) of each tray, and wherein said first apertures (90) extend in a position which is radially external
to an outer perimeter of said radial band.
In a 21 described aspect according to the preceding described aspect the apparatus has a peripheral formation (97)
which protrudes above the abutment surface (23a) of each seat (23) and which at least partially, preferably totally,
surrounds the respective radial band.
In a 22 described aspect according to the preceding described aspect said first apertures (90) are formed in
correspondence of corner zones (97c) of the peripheral formation.
In a 23 described aspect according to the preceding described aspect each first aperture (90) extends above the
abutment surface (23a) starting at a distance of at least 1, more preferably 2, mm from the abutment surface. This
means that each aperture has a contour delimited by said terminal edges whose minimum distance from the abutment
surface is 1mm or more.
In a 24 described aspect according to anyone of the preceding described aspects each seat (23) has a substantially
rectangular mouth (23c) defining first and second opposite sides connected by respective corner regions (23c), the
first apertures (90) being located at adjacent corner regions (23c) while the second apertures being located in
correspondence of one of said sides opposed to the corner regions where the first apertures are located.
In a 25 described aspect according to the preceding described aspect at each of said adjacent corner regions two or
more of said first apertures are provided.
In a 26 described aspect according to anyone of the preceding described aspects each of first conduits (91) leading
to the first apertures comprises at least an upwardly extending portion and a connection portion (98) located in
correspondence of one corner region (23c), the connection portion (98) defining an internal channel having a bottom
segment fluidly connected to said upwardly extending portion and a top segment extending transversally to said
upwardly extending portion and terminating into said terminal edges delimiting one or more of said first apertures (90).
In a 27 described aspect according to the preceding described aspect the area of fluid passage of said top segment
progressively increases proceeding towards the one or more first apertures forming a divergent tract.
In a 28 described aspect according to any one of the preceding two described aspects wherein each connection
portion (98) forms part of, optionally is integrally formed with, said peripheral formation (97) in correspondence of said
corner regions (23c).
In a 29 described aspect according to any one of the preceding three described aspects the packaging assembly (8)
comprises a plurality of said seats (23) the one being adjacently positioned with respect to the other and wherein the
connection portion (98) of one of said first conduits is interposed between two corner regions of two adjacent seats
(23), the connection portion defining one or more first apertures (90) facing one of the two adjacent seats and one or
more first apertures facing the other of said two adjacent seats.
In a 30 described aspect according to any one of the preceding described aspects the lower tool closure surface
facing the upper tool has a gripping member (99), optionally wherein the gripping member includes at least one
deformable piece anchored to said closure surface and surrounded by a flat surface, and
wherein the gripping member (99) is configured to cooperate with a corresponding opposite gripping surface (103)
carried by the upper tool, each gripping member and corresponding gripping surface - at least when the first and second
tools are in the second operating condition - being configured for therebetween engaging a peripheral portion of film
(10; 18), optionally a respective corner flap of said peripheral portion.
In a 30 described aspect according to the preceding described aspect wherein the lower tool comprises a plurality of
said gripping members located around each seat and wherein said gripping members are configured to cooperate with
corresponding gripping surfaces carried by the upper tool.
In a 32 described aspect according to any one of the preceding six described aspects each connection portion (98)
has a top side defining a gripping member (99), optionally wherein the gripping member includes at least one
deformable piece anchored to said top side and surrounded by a flat surface, and
wherein the gripping member (99) of each connection portion (98) is configured to cooperate with a corresponding
opposite gripping surface (103) carried by the upper tool, each gripping member and corresponding gripping surface -
at least when the first and second tools are in the second operating condition - being configured for therebetween
engaging a peripheral portion of film (10; 18), optionally a respective corner flap of said peripheral portion.
In a 33 described aspect according to any one of the preceding three described aspects each gripping surface (103)
is provided with a number, preferably a plurality, of suction holes (103a) connected to a suction system (104) controlled
by the control unit (100), the control unit commanding the suction system to suck gas via the suction holes to attract
the peripheral portion of film held by the upper tool (21).
In a 34 described aspect according to any one of the preceding described aspects the apparatus comprises:
a film supply assembly (5) configured to supply a continuous film (10),
a film cutting assembly (6) active on the continuous film (10) and configured for cutting discrete film sheets (18) of
prefixed length from said continuous film (10).
In a 35 described aspect according to the preceding described aspect the film cutting assembly (6) is located outside
said packaging chamber (24) and positioned between the film supply assembly and the packaging assembly.
th th
In a 36 described aspect according to the 34 described aspect, the film cutting assembly (6) is part of the packaging
assembly (8) and preferably carried by the upper tool (21).
In a 37 described aspect according to any one of the preceding three described aspects the film cutting assembly is
configured to cut film sheets of substantially polygonal, preferably rectangular, shape.
In a 38 described aspect according to any one of the preceding four described aspects at least one gripping member
(99) and corresponding gripping surface (103) are provided for each corner region (23c) of the seat mouth and wherein
each gripping member and corresponding gripping surface are configured for clamping therebetween a respective
peripheral portion or corner flap of said film sheet at least when the first and second tools are in the second operating
condition.
In a 39 described aspect according to any one of the preceding described aspects the apparatus has a vacuum
arrangement (27) connected to the packaging chamber (24) defined by the packaging assembly and part of the gas
evacuation circuit (96) for removing gas from said packaging chamber (24), said control unit (100) being further
configured to control the vacuum arrangement (27) to withdraw gas from said packaging chamber (24) at least when
the packaging assembly (8) is in said second operating condition with said packaging chamber (24) hermetically closed.
In a 40 described aspect according to any one of the preceding described aspects the apparatus has a controlled
atmosphere arrangement (30) connected to the packaging chamber (24) of the packaging assembly (8) and part of the
gas supply circuit (94) for injecting a stream of gas into said packaging chamber (24), said control unit (100) being
further configured to control said controlled atmosphere arrangement (30) to inject said stream of controlled gas at
least when the packaging assembly (8) is in said second operating condition with said packaging chamber (24)
hermetically closed; wherein the controlled atmosphere arrangement (30) is configured to inject gas into the packaging
chamber including a quantity of one or more of N , O and CO which is different from the quantity of these same gases
2 2 2
as present in the atmosphere at 20°C and sea level (1 atmosphere pressure).
In a 41 described aspect according to the preceding described aspect wherein the apparatus includes both the
vacuum arrangement (27) and the controlled atmosphere arrangement (30) and wherein the control unit (100) is
configured to control said controlled atmosphere arrangement (30) to start injecting said stream of controlled gas either
after a prefixed delay from activation of said vacuum arrangement (27) or after a prefixed level of vacuum has been
reached inside said packaging chamber (24), optionally wherein said control unit (100) is configured to control said
controlled atmosphere arrangement (30) to start injecting said stream of controlled gas while said gas withdrawal from
said packaging chamber is still ongoing.
In a 42 described aspect according to any one of the preceding two described aspects the control unit is configured
to operate the vacuum arrangement (27) for removing gas from said packaging chamber (24) and create in the
packaging chamber (24) a vacuum level with pressure comprised between 100 and 300 mbar, optionally between 150
and 250 mbar.
rd rd nd
In a 43 described aspect according to any one of the preceding described aspects from the 3 to the 42 the
packaging assembly (8) further comprises at least one main actuator (33) active on at least one of said upper and
lower tool (21; 22), the main actuator (33) being controlled by the control unit (100), the control unit (100) being
configured for acting on the main actuator (33) and commanding relative movement of the upper and lower tool (21;
22), along a main direction (A5), between said first operating condition, where the upper tool (21) is spaced apart from
the lower tool (22) and said packaging chamber (24) is open, and said second operating condition, where a closure
surface (34) of the upper tool (21) tightly abuts against a closure surface (35) of the lower tool (22) to hermetically close
said packaging chamber (24) with respect to an atmosphere outside the apparatus (1).
In a 44 described aspect according to the preceding described aspect an/the insert (36) of the upper tool is sized to
have an bottom surface (37) radially smaller than the abutment surface (33), wherein the insert (36) is peripherally
surrounded by a heating structure (40) having a respective heating surface (41) which extends radially outside with
respect to the bottom surface (37) of the insert (36), the insert (36) and the heating structure (40) being configured and
mounted for:
o the heating surface (41) of the heating structure (40) to overlap the abutment surface (23a) of a
respective one of said seats (23), at least when the packaging assembly (8) is in said second
operating condition, and
o the heating structure (40) and insert (36) to be relatively movable the one with respect to the other
along said main direction (A5) such that the heating surface (41) of the heating structure (40) is
selectively positionable at a position where its heating surface (41) does not contact a film contacting
the insert bottom surface (37), and in a position where the heating surface (41) contacts said film
(18);
th rd
In a 45 described aspect according to the 43 described aspect an/the insert (36) of the upper tool is sized such that
the insert (36) bottom surface (37) overlaps, optionally completely overlaps, the abutment surface (23a) of each seat
(23), at least when the packaging assembly (8) is in said second operating condition, the insert including at least one
heater configured for heating said bottom surface (37) or at least a portion of said bottom surface overlapping the
abutment surface (23).
In a 46 described aspect according to any one of the preceding two described aspects the heating surface (41) of the
heating structure (40) and/or the bottom surface (36) of the insert (37), has/have a substantially polygonal, preferably
rectangular, perimeter.
In a 47 described aspect according to any one of the preceding three described aspects the heating surface (41) of
the heating structure (40) and/or the bottom surface (36) of the insert (37), has/have a substantially polygonal perimeter
with rounded corners.
In a 48 described aspect according to the preceding described aspect the gripping member (99) and corresponding
gripping surface (103) at each said corner region (23c) operate in a position radially outside said heating surface
perimeter and/or radially outside bottom surface perimeter.
In a 50 described aspect according to any one of the preceding described aspects the apparatus comprises a frame
(2) carrying:
- a transport assembly (3), configured for displacing one or more trays to the packaging assembly,
- the packaging assembly (8),
- film supply assembly (5),
- film cutting assembly (6),
wherein the control unit (100) is configured for execution of the following cycle:
- commanding the transport assembly (3) to displace said trays (4) into packaging chamber (24) of
assembly (8);
- commanding the film cutting assembly (6) to at least transversally cut the continuous film (10) into
discrete film sheets (18),
- commanding the upper tool (21) to hold the cut film sheets or a portion of the film above, and at a
distance from, said tray (4),
- commanding the packaging assembly (8) to pass from the first to the second operating condition,
- commanding the controlled atmosphere arrangement (30) to inject a gas or a gas mixture in the
packaging chamber (24) via said first apertures (90), optionally wherein the control unit is configured for
commanding the controlled atmosphere arrangement (30) to inject a stream of gas after each gripping
member and corresponding gripping surface have a film peripheral portion,
- commanding the packaging assembly (8) to tightly fix the film sheet (18) to said support (4).
A 51 described aspect concerns a process of packaging a product (P) arranged on a tray (4) using the apparatus
(1) according to any one of the preceding claims.
In a 52 described aspect according to the preceding described aspect the process comprises the following steps:
- moving a film (10; 18) into the packaging chamber (24) of said packaging assembly (8),
- moving a tray (4) into the packaging chamber (24) and below said upper tool (21),
- causing the packaging assembly (8) to pass from the first to the second operating condition, optionally hermetically
closing the packaging chamber (24), with the film held above a number of said trays,
- injecting gas through said first apertures (90), preferably injecting a stream of controlled gas, the stream of
controlled gas being configured for creating a modified atmosphere within the packaging chamber (24);
- heat sealing the film sheet (18) to the tray (4), optionally after interrupting injection of gas through said first
apertures.
In a 53 described aspect according to the preceding described aspect cutting of the film (10a) into film sheets (18)
takes place outside the packaging chamber (24) and during injection of gas through said first apertures corner flaps
of film sheet are clamped between respective gripping members and gripping surfaces.
In a 54 described aspect according to any one of the preceding two described aspects the step of injecting gas
takes place through a plurality of first apertures (90) located at adjacent corner regions of a same seat mouth.
In a 55 described aspect according to the preceding described aspect the injected gas streams are directed parallel
to the abutment surface (23a) and towards a center of the respective seat (23).
In a 56 described aspect according to any one of the preceding four described aspects the step of injecting gas
takes place through first apertures (91) of ejectors (92) and comprises ejecting a gas stream - through said ejectors -
tangential and parallel to the abutment surface (23b) of seat (23) and tangential and parallel with respect to a tray
flange (4c) resting above said abutment surface (23b) of seat (23).
In a 57 described aspect according to any one of the preceding five described aspects the first apertures (90) are
located and entirely extend above the abutment surface (23a) and the step of injecting comprises ejecting a gas
stream through said ejectors which flows entirely above the abutment surface (23b) of seat (23) and above a tray
flange (4c) resting on abutment surface (23b) of seat (23).
Brief description of the drawings
The present invention will become clearer by reading the following detailed description, given by way of example and
not of limitation, to be read with reference to the accompanying drawings, wherein:
is a schematic side view layout of a first embodiment of an apparatus according to described aspects herein.
is a schematic side view layout of a second embodiment of an apparatus according to described aspects
herein.
FIGs. 2-13 are schematic side views relating to a packaging assembly of the apparatus of figure 1, according to further
described aspects herein. In these figures, consecutive phases of a packaging process operated by the apparatus of
the first embodiment are shown. The apparatus and process according to these figures relate to a case where a
continuous film is severed into discrete film sheets of appropriate shape and size before each film sheet is transported
inside the packaging assembly and positioned above the respective tray. The apparatus and process shown in these
figures are intended for tray lidding with formation of a controlled atmosphere inside the package. However, it is not
excluded that the apparatus may also be used to form a skin packaging.
FIGs. 14-22 are schematic side views relating to a packaging assembly of the apparatus of figure 1A, according to
other described aspects herein. In these figures, consecutive phases of a packaging process operated by the apparatus
of the second embodiment are shown. The apparatus and process according to these figures relate to a case where a
continuous film is unrolled and moved into the packaging assembly and above one or more trays. Once the desired
film portion is properly positioned in the packaging assembly, the continuous film is severed into discrete film sheets
of appropriate shape and size which are tightly fixed to the respective tray. The severing may take place before, during
or after the film is fixed to the tray or trays. The apparatus and process shown in these figures are intended for tray
lidding with formation of a controlled atmosphere inside the package. However, it is not excluded that the apparatus
may also be used to form a skin packaging.
is a schematic view taken from the bottom of a tray located in the packaging assembly of any one of above
embodiments. This figure shows a tray, a film sheet overlapping the tray, and the overlying upper tool of the packaging
assembly.
is a cross section of a packaging assembly which may be used in the first and second embodiment of the
apparatus. The packaging assembly is shown in correspondence of a second operation condition where it forms a
packaging chamber. The cross section is taken along a plane (represented with trace XXIV-XXIV) passing through
corners of a tray seat located inside the packaging assembly where a tray is positioned during the packaging process.
is a cross section of the packaging assembly of figure 24 taken along a plane (represented with trace XXV-
XXV in figure 23) angularly shifted of 45° with respect to the section plane of figure and therefore not passing through
said corners.
shows in perspective a detail of the lower tool of the packaging assembly according to a variant described
herein which may be used in the first and second embodiment of the apparatus. According to this variant the lower tool
includes a plurality of seats for receiving a corresponding plurality of trays.
Figures 27A and 28 represent a further detail concerning the first apertures used for injection (and/or withdrawing) gas
from the packaging chamber, according to described aspects herein which may be used in the first and second
embodiment of the apparatus.
Figure 27B shows a variant of the particular shown in figure 27A.
Figure 29 shows a portion of figure 26 and emphasizes the direction of the injected gas flow streams during gas: as
shown in this figure the first apertures are present on two adjacent corner regions of a seat mouth and second apertures
used for evacuating gas are located on the side of the seat mouth opposite to said two adjacent corner regions.
Definitions and conventions
In the present detailed description corresponding parts shown in the various figures are indicated with the same
reference numerals through the figures. It is further noted that the figures are not to scale and the parts and components
shown therein are schematic representations.
In the following description and claims the apparatus and process refer to packaging of a product inside a tray. The
product may be a food product or other product. As used herein, tray 4 denotes a container of the type having a base
wall 4a, a side wall 4b, and a flange which is a top flange 4c radially emerging from the side wall 4b. The tray 4 top
flange 4c may have polygonal, in particular rectangular, shape. Note that with polygonal or rectangular shape it is
intended that the overall appearance of the outer peripheral edge of the top flange is polygonal or rectangular, with
corner regions which may be rounded. Trays may be manufactured by thermoforming or injection molding. In certain
applications of the invention, the apparatus and process may also operate with trays 4 having a side wall with height
sensibly reduced with respect to the radial size of the tray, such that the tray takes the shape of a substantially flat
support with a slight central depression on the top surface thereof: for example the depression may be configured to
receive laminar products such as for example slices of chees, meat, ham etc.. The side wall may also be substantially
absent such that the tray degenerates in a support of flat or plate like conformation whereby the tray flange 4c is defined
by a tray peripheral border.
The trays
The trays 4 described and claimed herein may be made of a single layer or, preferably, of a multi-layer polymeric
material.
In case of a single layer material, suitable polymers include, for example, polystyrene, polypropylene, polyesters, high
density polyethylene, poly(lactic acid), PVC, and the like, either foamed or solid.
Preferably the tray 4 is provided with gas barrier properties. As used herein such term refers to a film or sheet of
3 2 3 2
material which has an oxygen transmission rate of less than 200 cm /m ·day·atm, less than 150 cm / m ·day·atm, less
than 100 cm / m ·day·atm as measured according to ASTM D-3985 at 23°C and 0% relative humidity. Suitable
materials for gas barrier monolayer thermoplastic trays 4 are, for example, polyesters, polyamides and the like.
In case the tray 4 is made of a multi-layer material, suitable polymers are, for example, ethylene homo- and co-
polymers, propylene homo- and co-polymers, polyamides, polystyrene, polyesters, poly(lactic acid), PVC and the like.
Part of the multi-layer material can be solid and part can be foamed.
For example, the tray 4 may comprise at least one layer of a foamed polymeric material chosen from the group
consisting of polystyrene, polypropylene, polyesters and the like.
The multi-layer material may be produced either by co-extrusion of all the layers using co-extrusion techniques or by
glue- or heat-lamination of, for example, a rigid foamed or solid substrate with a thin film, usually called “liner”.
The thin film may be laminated either on the side of the tray 4 in contact with the product P or on the side facing away
from the product P or on both sides. In the latter case the films laminated on the two sides of the tray 4 may be the
same or different. A layer of an oxygen barrier material, for example (ethylene-co-vinyl alcohol) copolymer, is optionally
present to increase the shelf-life of the packaged product P.
Gas barrier polymers that may be employed for the gas barrier layer are PVDC, EVOH, polyamides, polyesters and
blends thereof. The thickness of the gas barrier layer will be set in order to provide the tray with an oxygen transmission
rate suitable for the specific packaged product.
The tray may also comprise a heat sealable layer. Generally, the heat-sealable layer will be selected among the
polyolefins, such as ethylene homo- or co-polymers, propylene homo- or co-polymers, ethylene/vinyl acetate
copolymers, ionomers, and the homo- and co-polyesters, e.g. PETG, a glycol-modified polyethylene terephthalate.
Additional layers, such as adhesive layers, to better adhere the gas-barrier layer to the adjacent layers, may be present
in the gas barrier material for the tray and are preferably present depending in particular on the specific resins used for
the gas barrier layer.
In case of a multilayer material used to form the tray 4, part of this structure may be foamed and part may be un-
foamed. For example, the tray 4 may comprise (from the outermost layer to the innermost food-contact layer) one or
more structural layers, typically of a material such as foam polystyrene, foam polyester or foam polypropylene, or a
cast sheet of e.g. polypropylene, polystyrene, poly(vinyl chloride), polyester or cardboard; a gas barrier layer and a
heat-sealable layer.
The tray 4 may be obtained from a sheet of foamed polymeric material having a film comprising at least one oxygen
barrier layer and at least one surface sealing layer laminated onto the side facing the packaged product, so that the
surface sealing layer of the film is the food contact layer the tray. A second film, either barrier or non-barrier, may be
laminated on the outer surface of the tray.
Specific tray formulations are used for food products that require heating in a conventional or microwave oven before
consumption. The surface of the container in contact with the product, i.e. the surface involved in the formation of the
seal with the lidding film, comprises a polyester resin. For example, the container can be made of a cardboard coated
with a polyester resin or it can be integrally made of a polyester resin. Examples of suitable containers for the package
described herein are CPET, APET or APET/CPET containers. Such containers can be either foamed or not foamed.
Trays 4 used in tray lidding or skin packaging applications containing foamed parts, have a total thickness lower than
8 mm, and, for example, may be comprised between 0.5 mm and 7.0 mm, more frequently between 1.0 mm and 6.0
mm.
In case of a rigid tray not containing foamed parts, the total thickness of the single-layer or multi-layer thermoplastic
material is preferably less than 2 mm, and, for example, may be comprised between 0.1 mm and 1.2 mm, more
frequently between 0.2 mm and 1.0 mm.
The film or film material
The film or film material described herein may be applied to the tray 4 to form a lid on the tray (e.g. for MAP - modified
atmosphere packaging) or a skin-like cover in contact with the tray and product, and matching the contour of the
product.
The film for skin packaging applications may be made of a flexible multi-layer material comprising at least a first outer
heat-sealable layer, an optional gas barrier layer and a second outer heat-resistant layer. The outer heat-sealable layer
may comprise a polymer capable of welding to the inner surface of the supports carrying the products to be packaged,
for example, ethylene homo- or co-polymers, like LDPE, ethylene/alpha-olefin copolymers, ethylene/acrylic acid
copolymers, ethylene/methacrylic acid copolymers, and ethylene/vinyl acetate copolymers, ionomers, co-polyesters
(e.g. PETG).
The optional gas barrier layer preferably comprises oxygen impermeable resins like PVDC, EVOH, polyamides and
blends of EVOH and polyamides. The outer heat-resistant layer may be made of ethylene homo- or copolymers,
ethylene/cyclic-olefin copolymers, such as ethylene or norbornene copolymers, propylene homo- or co-polymers,
ionomers, (co)polyesters, (co)polyamides.
The film may also comprise other layers such as adhesive layers or bulk layers to increase the thickness of the film
and improve its properties regarding resistance and deep drawing. In particular, ionomers, ethylene/vinyl acetate
copolymers, polyamides and polyesters are used in bulk layers. In all layers of the film, the polymer components may
contain appropriate amounts of additives normally included in such compositions. Some of these additives are
preferably included in the outer layers or in one of the outer layers, while some others are preferably added to inner
layers. These additives include slip and anti-block agents such as talc, waxes, silica, and the like, antioxidants,
stabilizers, plasticizers, fillers, pigments and dyes, cross-linking inhibitors, cross-linking enhancers, UV absorbers, odor
absorbers, oxygen scavengers, bactericides, antistatic agents and the like additives known to those skilled in the art
of packaging films.
One or more layers of the film can be cross- linked to improve the strength of the film and/or its heat resistance. Cross-
linking may be achieved by using chemical additives or by subjecting the film layers to an energetic radiation treatment.
The films for skin packaging are typically manufactured in order to show low shrink when heated during the packaging
cycle. Those films usually shrink less than 15% at 160°C, more frequently lower than 10%, even more frequently lower
than 8% in both the longitudinal and transversal direction (ASTM D2732). The films usually have a thickness comprised
between 20 microns and 200 microns, more frequently between 40 and 180 microns, and even more frequently
between 50 microns and 150 microns.
The skin packages are usually “easy-to-open”, i.e. they are easily openable by manually pulling apart the two webs,
normally starting from a point like a corner of the package where the upper web has purposely not been sealed to the
support. To achieve this feature, either the film or the tray can be provided with a suitable composition, allowing easy
opening of the package as known in the art. Typically, the sealant composition and/or the composition of the adjacent
layer of the tray and/or the film are adjusted in order to achieve the easy opening feature.
Various mechanisms can occur while opening an easy-to-open package.
In the first one ("peelable easy opening"), the package is opened by separating the film and the tray at the seal
interface.
In the second mechanism ("adhesive failure") the opening of the package is achieved through an initial breakage
through the thickness of one of the sealing layers followed by delamination of this layer from the underlying support
or film.
The third system is based on the "cohesive failure" mechanism. The easy opening feature is achieved by internal
rupture of a seal layer that, during opening of the package, breaks along a plane parallel to the layer itself.
Specific blends are known in the art to obtain such opening mechanisms, ensure the peeling of the film from the tray
surface, such as those described in EP1084186.
On the other hand, in case the film 10a is used for creating a lid on the tray 4, the film material may be obtained by
co-extrusion or lamination processes. Lid films may have a symmetrical or asymmetrical structure and can be of a
single layer or multilayer type.
The multilayer films have at least 2, more frequently at least 5, and even more frequently at least 7 layers.
The total thickness of the film may vary from 3 to 100 micron, more frequently from 5 to 50 micron, even more
frequently from 10 to 30 micron. The films may optionally be cross-linked. Cross-linking may be carried out by
irradiation with high energy electrons at a suitable dosage level as known in the art. The lid films described above
may be heat shrinkable or heat-set. The heat shrinkable films typically show a free shrink value measured at 120°C
according to ASTM D2732 in the range of from 2 to 80%, more frequently from 5 to 60%, even more frequently from
to 40% in both the longitudinal and the transverse direction. The heat-set films usually have free shrink values
lower than 10% at 120°C, preferably lower than 5% in both the longitudinal and transversal direction (ASTM D 2732).
Lid films usually comprise at least a heat sealable layer and an outer skin layer, which is generally made up of heat
resistant polymers or polyolefin. The sealing layer typically comprises a heat-sealable polyolefin which in turn
comprises a single polyolefin or a blend of two or more polyolefins such as polyethylene or polypropylene or a blend
thereof. The sealing layer can be further provided with anti-fogging properties by incorporating one or more anti-fogging
additives into its composition or by coating or spraying one or more anti-fogging additives onto the surface of the sealing
layer by technical means known in the art.
The sealing layer may further comprise one or more plasticizers. The skin layer may comprises polyesters, polyamides
or polyolefin. In some structures, a blend of polyamide and polyester can advantageously be used for the skin layer.
In some cases, the lid films comprise a barrier layer. Barrier films typically have an OTR (evaluated at 23°C and 0 %
3 2 3 2
R.H. according to ASTM D-3985) below 100 cm /(m ·day·atm) and more frequently below 80 cm /(m ·day·atm). The
barrier layer is usually made of a thermoplastic resin selected among a saponified or hydrolyzed product of ethylene-
vinyl acetate copolymer (EVOH), an amorphous polyamide and a vinyl-vinylidene chloride and their admixtures. Some
materials comprise an EVOH barrier layer, sandwiched between two polyamide layers. The skin layer typically
comprises polyesters, polyamides or polyolefin.
In some packaging applications, the lid films do not comprise any barrier layer. Such films usually comprise one or
more polyolefin herein defined. Non-barrier films typically have an OTR (evaluated at 23°C and 0 % R.H.
3 2 3 2
according to ASTM D-3985) from 100 cm /(m ·day·atm) up to 10000 cm /(m ·day·atm), more typically up to
6000 cm /(m ·day·atm).
Peculiar polyester-based compositions are those used for tray lidding of ready-to-eat meal packages. For these films,
the polyester resins can make up at least 50%, 60%, 70%, 80%, or 90% by weight of the film. These films are
typically used in combination with polyester-based supports.
For example, the container can be made of a cardboard coated with a polyester resin or it can be integrally made of a
polyester resin. Examples of suitable containers for the package are CPET, APET or APET/CPET containers, either
foamed or not foamed.
Usually, biaxially oriented PET is used as the lid film due to its high thermal stability at standard food heating/cooking
temperatures. Often biaxially oriented polyester films are heat-set, i.e. non-heat-shrinkable. To improve the heat-
sealability of the PET lidding film to the container a heat-sealable layer of a material with a lower melting point is
usually provided on the film. The heat-sealable layer may be coextruded with the PET base layer (as disclosed in
EP-A-1529797 and WO2007/093495) or it may be solvent- or extrusion-coated over the base film (as disclosed in US
2,762,720 and EP-A-1252008).
Particularly in the case of fresh meat packages, twin lidding film comprising an inner, oxygen-permeable, and an
outer, oxygen-impermeable, lidding film are advantageously used. The combination of these two films significantly
prevents the meat discoloration also when the packaged meat extends upwardly with respect to the height of the tray
walls, which is the most critical situation in barrier packaging of fresh meat. These films are described for example in
EP1848635 and EP0690012, the disclosures of which are incorporated herein by reference. In some examples, twin
lidding film can be made by sealing two suitable films in the region of the corners by means of very small bonding or
sealing points. In this manner, the twin lidding film can be handled more easily in the different stages of the
packaging process.
The lid film can be monolayer. Typical composition of monolayer films comprise polyesters as herein defined and
their blends, or polyolefins as herein defined and their blends.
In all the film layers described herein, the polymer components may contain appropriate amounts of additives
normally included in such compositions. Some of these additives are preferably included in the outer layers or in one
of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-
block agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes,
cross-linking inhibitors, cross-linking enhancers, UV absorbers, odor absorbers, oxygen scavengers, bactericides,
antistatic agents, anti-fogging agents or compositions, and the like additives known to those skilled in the art of
packaging films.
The films suitable for lidding applications can advantageously be perforated, in order to allow the packaged food to
breath.
Those films may be perforated by using different technologies available in the art, through laser or mechanical
means such as rolls provided with several needles.
The number of perforations per unit area of the film and their dimensions affect the gas permeability of the film.
Micro perforated films are usually characterized by OTR value (evaluated at 23°C and 0 % R.H. according to ASTM
3 2 3 2
D-3985) from 2500 cm /(m ·day·atm) up to 1000000 cm /(m ·day·atm).
Macro perforated films are usually characterized by OTR (evaluated at 23°C and 0 % R.H. according to ASTM D-
3985) higher than 1000000 cm /(m ·day·atm).
Furthermore, the films herein described for lidding applications can be formulated to provide strong or peelable
sealing onto the support. A method of measuring the force of a peelable seal, herein referred to as “peel force” is
described in ASTM F00. Acceptable peel force values fare in the range from 100 g/25 mm to 850 g/25 mm, from
150 g/25 mm to 800 g/25 mm, from 200 g/25 mm to 700 g/25 mm.
The desired seal strength is achieved specifically designing the tray and the lid formulations.
In general, one or more layers of the lid film can be printed, in order to provide useful information to the consumer, a
pleasing image and/or trademark or other advertising information to enhance the retail sale of the packaged product.
The film may be printed by any suitable method, such as rotary screen, gravure or flexographic techniques as known
in the art.
Definitions and conventions concerning materials
PVDC is any vinylidene chloride copolymers wherein a major amount of the copolymer comprises vinylidene chloride
and a minor amount of the copolymer comprises one or more unsaturated monomers copolymerizable therewith,
typically vinyl chloride, and alkyl acrylates or methacrylates (e.g. methyl acrylate or methacrylate) and the blends
thereof in different proportions. Generally a PVDC barrier layer will contain plasticizers and/or stabilizers as known in
the art.
The term “comprising” as used in this specification and claims means “consisting at least in part of”. When interpreting
statements in this specification and claims which include the term “comprising”, other features besides the features
prefaced by this term in each statement can also be present. Related terms such as “comprise” and “comprised” are
to be interpreted in similar manner.
As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers, and refers to
ethylene/vinyl alcohol copolymers having an ethylene co-monomer content preferably comprised from about 28 to
about 48 mol%, more preferably, from about 32 to about 44 mol% ethylene, and even more preferably, and a
saponification degree of at least 85%, preferably at least 90%.
The term “polyamides” as used herein is intended to refer to both homo- and co- or ter-polyamides. This term
specifically includes aliphatic polyamides or co-polyamides, e.g., polyamide 6, polyamide 11, polyamide 12, polyamide
66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide
6/66, copolyamide 6/69, aromatic and partially aromatic polyamides or co-polyamides, such as polyamide 6I, polyamide
6I/6T, polyamide MXD6, polyamide MXD6/MXDI, and blends thereof.
As used herein, the term “copolymer” refers to a polymer derived from two or more types of monomers, and includes
terpolymers. Ethylene homopolymers include high density polyethylene (HDPE) and low density polyethylene (LDPE).
Ethylene copolymers include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers.
Ethylene/alpha-olefin copolymers generally include copolymers of ethylene and one or more co-monomers selected
from alpha-olefins having from 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl
pentene and the like.
Ethylene/alpha-olefin copolymers generally have a density in the range of from about 0.86 to about 0.94 g/cm3. The
term linear low density polyethylene (LLDPE) is generally understood to include that group of ethylene/alpha-olefin
copolymers which fall into the density range of about 0.915 to about 0.94 g/cm and particularly about 0.915 to about
0.925 g/cm . Sometimes linear polyethylene in the density range from about 0.926 to about 0.94 g/cm is referred to
as linear medium density polyethylene (LMDPE). Lower density ethylene/alpha-olefin copolymers may be referred to
as very low density polyethylene (VLDPE) and ultra-low density polyethylene (ULDPE). Ethylene/alpha-olefin
copolymers may be obtained by either heterogeneous or homogeneous polymerization processes.
Another suitable ethylene copolymer is an ethylene/unsaturated ester copolymer, which is the copolymer of ethylene
and one or more unsaturated ester monomers. Suitable unsaturated esters include vinyl esters of aliphatic carboxylic
acids, where the esters have from 4 to 12 carbon atoms, such as vinyl acetate, and alkyl esters of acrylic or methacrylic
acid, where the esters have from 4 to 12 carbon atoms.
Ionomers are copolymers of an ethylene and an unsaturated monocarboxylic acid having the carboxylic acid
neutralized by a metal ion, such as zinc or, preferably, sodium.
Useful propylene copolymers include propylene/ethylene copolymers, which are copolymers of propylene and ethylene
having a majority weight percent content of propylene, and propylene/ethylene/butene terpolymers, which are
copolymers of propylene, ethylene and 1-butene.
As used herein, the term "polyolefin" refers to any polymerized olefin, which can be linear, branched, cyclic, aliphatic,
aromatic, substituted, or unsubstituted. More specifically, included in the term polyolefin are homo-polymers of olefin,
co-polymers of olefin, co-polymers of an olefin and an non-olefinic co-monomer co-polymerizable with the olefin, such
as vinyl monomers, modified polymers thereof, and the like. Specific examples include polyethylene homo-polymer,
polypropylene homo-polymer, polybutene homo-polymer, ethylene-alpha-olefin co-polymer, propylene-alpha-olefin co-
polymer, butene-alpha-olefin co-polymer, ethylene-unsaturated ester co-polymer, ethylene-unsaturated acid co-
polymer, (e.g. ethylene-ethyl acrylate co-polymer, ethylene-butyl acrylate co-polymer, ethylene-methyl acrylate co-
polymer, ethylene-acrylic acid co-polymer, and ethylene-methacrylic acid co-polymer), ethylene-vinyl acetate
copolymer, ionomer resin, polymethylpentene, etc.
The term "polyester" is used herein to refer to both homo-and co- polyesters, wherein homo-polyesters are defined as
polymers obtained from the condensation of one dicarboxylic acid with one diol and co-polyesters are defined as
polymers obtained from the condensation of one or more dicarboxylic acids with one or more diols. Suitable polyester
resins are, for example, polyesters of ethylene glycol and terephthalic acid, i.e. poly(ethylene terephthalate) (PET).
Preference is given to polyesters that contain ethylene units and include, based on the dicarboxylate units, at least 90
mol%, more preferably at least 95 mol%, of terephthalate units. The remaining monomer units are selected from other
dicarboxylic acids or diols. Suitable other aromatic dicarboxylic acids are preferably isophthalic acid, phthalic acid, 2,5-
, 2,6- or 2,7-naphthalenedicarboxylic acid. Of the cycloaliphatic dicarboxylic acids, mention should be made of
cyclohexanedicarboxylic acids (in particular cyclohexane-1,4-dicarboxylic acid). Of the aliphatic dicarboxylic acids, the
(C -Ci )alkanedioic acids are particularly suitable, in particular succinic acid, sebacic acid, adipic acid, azelaic acid,
suberic acid or pimelic acid. Suitable diols are, for example aliphatic diols such as ethylene glycol, diethylene glycol,
triethylene glycol, propylene glycol, 1,3-butane diol, 1,4- butane diol, 1,5-pentane diol, 2,2-dimethyl-1,3-propane diol,
neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4- cyclohexanedimethanol and 1,4-
cyclohexane diol, optionally heteroatom- containing diols having one or more rings.
Co-polyester resins derived from one or more dicarboxylic acid(s) or their lower alkyl (up to 14 carbon atoms) diesters
with one or more glycol(s), particularly an aliphatic or cycloaliphatic glycol may also be used as the polyester resins for
the base film. Suitable dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid,
phthalic acid, or 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as succinic acid,
sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable glycol(s) include aliphatic diols such as
ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane
diol, 2,2- dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4-
cyclohexanedimethanol and 1,4- cyclohexane diol. Examples of such copolyesters are (i) copolyesters of azelaic acid
and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; (ii) copolyesters of adipic acid and terephthalic
acid with an aliphatic glycol, preferably ethylene glycol; and (iii) copolyesters of sebacic acid and terephthalic acid with
an aliphatic glycol, preferably butylene glycol; (iv) co-polyesters of ethylene glycol, terephthalic acid and isophthalic
acid. Suitable amorphous co-polyesters are those derived from an aliphatic diol and a cycloaliphatic diol with one or
more, dicarboxylic acid(s), preferably an aromatic dicarboxylic acid. Typical amorphous copolyesters include co-
polyesters of terephthalic acid with an aliphatic diol and a cycloaliphatic diol, especially ethylene glycol and 1,4-
cyclohexanedimethanol.
Detailed description
First embodiment of the apparatus 1
The description of the first embodiment makes reference to figures from 1 to 13 and from 23 to 28. In particular note
that figures 23 to 28 disclose described aspects which may be present either in the first embodiment described in this
section of the description and also in the second embodiment described in a subsequent section of the present
description.
FIGs. 1-13 show an apparatus 1 for packaging of a product P arranged on tray 4 according to an embodiment described
herein. The apparatus 1 is adapted for modified atmosphere packaging, where a plastic film 18 is applied to the top
flange 4c of a tray 4 after a modified gas atmosphere has been created inside the tray 4, and/or for vacuum skin
packaging of the product P, where a thin film of plastic material is draped down on the product and intimately adheres
to a top flange and to the inner surface of the support as well as to the product surface thus leaving a minimum, if any,
amount of air or modified gas within the packaging. The apparatus 1 may also be used in case a film sheet applied to
a tray and neither vacuum nor modified atmosphere is created.
The apparatus 1 comprises a frame 2, a transport assembly 3 for displacing the tray 4, a film supplying assembly 5, a
film cutting assembly 6, a transfer device 7 and a packaging assembly 8.
The tray 4 shown in the enclosed figures presents a base wall 4a, a side wall 4b emerging from the base wall and
delimiting a space where a product P can be housed, and a top flange 4c radially protruding from the side wall 4b: in
the example shown the top flange 4c has a horizontal flat portion defining a suitable sealing surface for sealed fixing
of a plastic film.
The frame 2 defines a base body of the apparatus 1 and serves to carry and support various parts of the apparatus 1
as herein described.
The transport assembly 3 comprises a displacement plane 20, which may be a physical plane (e.g. a conveyor belt)
carrying and displacing the trays or an ideal plane along which the trays are guided e.g. by means of rails or guides.
The plane 20 is defined on a top area of the frame and a conveyor 46 is arranged in correspondence of the sliding
plane 20. In the example shown, the transport assembly 3 is carried by, e.g. fixed to, the frame 2 so that the sliding
plane 20 is substantially horizontal and the conveyor 46 moves the trays 4 according to the horizontal direction
indicated by the arrow A1 shown in The transport assembly 3 arranged on the frame 2 is configured for
displacing the tray 4 along a predefined path from a loading station, where trays 4 which may already be filled with the
respective product(s) P are positioned, to the packaging assembly 8 where a film 18 is tightly fixed to each tray 4, as
explained in detail below. The conveyor 46 displaces the trays (e.g. a prefixed number of trays each time) towards and
into the packaging chamber, into proper position for receiving the film. For example, a control unit 100 (which is further
described below) may control the conveyor 46 to displace a prefixed number of trays 4 each time from a region outside
the packaging assembly, to a region within the packaging assembly where the tray or trays are directly below or in
superimposition with the film to be fixed to the tray. The conveyor may, for example, include a first transfer device 46a
(such as the belt shown in configured for bringing the trays in close proximity to the packaging assembly and
a second transfer device 46b adapted to pick up one or more of said trays and to bring them into the packaging
assembly 8. The second transfer device may, for example, include actuators or arms acting on the sides of the trays
such as to pick up the supports from the first transfer device, to bring them into the packaging station, and then to
return to the first transfer devise to pick up a new set of trays 4. Alternatively, the conveyor 46 may include pushers
(e.g. in the form of bars extending transverse to said direction A1) acting on the trays and pushing the trays into the
packaging assembly 8. The pushers may be moved by chains or belts and may be moved into the packaging assembly
to properly position a number of trays, and then be retracted from the packaging assembly, once the trays have reached
their proper position inside the packaging assembly. In some examples, the pushers can be integrated into the
packaging assembly in a manner not interfering with the process taking place inside the packaging assembly. In these
examples, the pushers are first extended in order to retrieve a number of trays and move them into the packaging
assembly, and then retracted until opening of the packaging assembly following the execution of the process taking
place inside the packaging assembly. According to a further alternative, the conveyor 46 may include housings (e.g. in
the form of plates provided with cavities for receiving a number of trays) which are moved along said direction A1 and
which are moving inside the packaging station together with the supports or trays 4. According to this alternative, the
housings have a suitable shape in order to be hosted inside the packaging station during the application of the film to
the tray 4.
It is noted that the products P may be positioned on the tray 4 either upstream from the loading station or in any location
between the loading station and the packaging assembly 8. Also, in accordance with a further alternative which is not
shown in the enclosed drawing tables, the trays may be thermoformed online from a continuous film and then fed to
the packaging assembly 8. The transport assembly 3 further comprises a motor 9 (e.g. a stepping motor unit) for
operating the conveyor belt 46 with a continuous or step-by-step movement.
The film supply assembly 5 may comprise a film roll 11 supplying a continuous film 10. The film supplying assembly 5
may further comprise a roll support arm 11a (represented in dashed lines in fixed to the frame 2 and suitable
for supporting the film roll. Further, the film supplying assembly 5 may comprise film punching devices (not shown, as
these are known in the art) essentially configured to provide the correct profile to the film edges to match (when
transversally cut in the cutting assembly 6) the shape of the tray 4 opening. The punching devices may also help to
keep an unrolled portion of film pulled from the film roll 11 aligned according to a prefixed direction. The film supplying
assembly 5 may also comprise pinch rollers 12 and/or other means for pulling the film 10 from the film roll 11 and
properly position it in correspondence of the film cutting assembly 6 (e.g., said means may comprise pincers acting on
the side of the film and/or pincers acting on the front edge or side edges of the film) and configured to pull the film. The
type of film 10 rolled up on the film roll 11 and may correspond to one of the types of film described above, depending
upon the specific application.
The film cutting assembly 6 shown in the figures is an exemplary cutting assembly illustrating one of several alternatives
for cutting film 10 into discrete film sheets 18. The film 10 could be pre-cut in sheets at another location and provided
in the form of stacks of film sheets ready for heat sealing. In the embodiment of figure 1, the film 10 is cut locally, for
example by a cutting assembly (such as cutting assembly 6) located external to the packaging chamber 24 defined by
packaging assembly 8. The cutting assembly is configured for forming a sequence of film sheets 18 which are then
supplied to the packaging assembly 8. In both cases, the sheets of film 18, either pre-cut or cut online, are picked by
transfer device 7 and transferred into the packaging assembly. Alternatively a component of the packaging apparatus
(for example a part of the packaging assembly) is actuated and moved into a pick-up position, where the component
can pick up a single film sheet 18, and then moved back to the packaging assembly or packaging chamber, in order to
properly position the film sheet 18 above a respective tray 4.
The film cutting assembly 6 comprises a cutting device 13 with a blade 14 and a blade piston 15. This piston 15 may
be replaced by any other kind of electric, pneumatic, or hydraulic (linear) actuator. The blade piston 15 is preferably
fixed to the frame 2 and is connected to the cutting device 13 so as to push and pull it in a direction transverse to the
unrolled portion of the film 10, as indicated by the double arrow A2 shown in The film cutting assembly 6 is
described here, illustrating one possibility of supplying the film to the packaging apparatus. In some examples,
however, the film material can be supplied in a manner where the film is pre-cut and supplied, for example, on a sheet
by sheet basis, delivered from a stack of pre-cut film sheets.
In order to move the cut sheets of film 18 into the packaging assembly 8 of the packaging apparatus 1 according to a
first embodiment, the transfer device 7 is used. The transfer device 7 includes a backing structure 16 having a flat
holding surface 17 adapted for receiving the at least one or more film sheets 18 cut by blade 14. While backing structure
16 is described here and shown in the figures as having a substantially flat holding surface 17, it is noted that the
holding surface 17 does not have to be flat, but can have any suitable shape (e.g., concave, convex, corrugated, having
some texture, having protrusions and/or recesses, etc.). shows that the blade 14 is configured to cut the
continuous film 10 such that a separate sheet of film 18 can be positioned in correspondence of the flat holding surface
17. The backing structure 16 may hold the cut film sheet 18 using one or more of:
- a vacuum system connected to one or more channels present in the backing structure and leading to apertures
located one holding surface 17,
- mechanical holders, such as pincers, clamps or the like,
- adhesive systems, for example comprising adhesive portions associated to the holding surface 17,
- heating systems, for example comprising heatable portions (controlled by control unit 100) associated to the
backing structure causing heating of the holding surface 16 and thus of the film sheet 18 in order to increase
stickiness of the film sheet to the holding surface 17,
- electric systems, for example the holding surface may be charged with a polarity different from that typical of
the plastic sheet 18. In this case the control unit may be connected to a voltage generator and may control
the electric charging of surface 17.
The transfer device 7 also includes a mechanism, for example carried by frame 2, active on the backing structure 16
and configured for relatively moving the backing structure 16 with respect to the packaging assembly 8 between a first
position, shown in where the baking structure 16 is positioned near the cutting device, for example immediately
downstream the blade 14 with respect to the movement imposed to film 10, and at least a second position, where the
backing structure 16 is positioned inside the packaging chamber 24 of the packaging assembly 8. For example, the
mechanism includes a transfer actuator active on the backing structure 16 and configured for moving the backing
structure 16 along a path suitable for achieving the displacement between said first and second positions. The transfer
actuator may be any kind of electric, pneumatic or hydraulic actuator known in the art and suitable for actuating the
backing structure in the required manner. As an alternative, instead of moving the backing structure 16, an upper tool
21 of the packaging assembly 8 may be mobile with respect to frame 2 and be configured to pick the cut film sheets
18 from the area immediately downstream the cutting device 13. In this case the transfer device 7 would include a
mechanism 25, for example carried by frame 2, active on the packaging assembly 8 and configured for displacing the
upper tool 21 between a first position, where the upper tool 21 is positioned in correspondence of the backing structure
16 and configured to pick up from the backing structure 16 the one or more cut film sheets 18, and at least a second
position, where the upper tool 21 is aligned to the lower tool 22 and configured to position at least one film sheet 18
above said tray 4. In order to achieve the above movement the mechanism may displace the upper tool 21 along any
suitable path. For example, schematically shows that the mechanism 25 may include a transfer actuator 26
configured for displacing the upper tool 21 at least along a direction parallel to said horizontal direction A1 as indicated
by double arrow A4 in and to rotate the upper tool around an axis which is horizontal and perpendicular with
respect to direction A4, so that the lower end thereof faces the backing structure 16 in order to pick up the film sheets
18. Alternatively the mechanism 25 may cause rotation of the upper tool around a pivoting axis and/or a translational
displacement in order to move the upper tool between the respective positions along an appropriate path. The transfer
actuator 26 may comprise any kind of electric, pneumatic or hydraulic actuators or combinations thereof known in the
art.
Moving now to a more detailed description of the packaging assembly 8, it should be noted that the packaging assembly
is mainly devoted to tightly fixing the film (in the case of first embodiment in the form of film sheets 18) to one or more
trays 4. At this purpose, the packaging assembly 8 has a lower tool 22 defining a prefixed number of seats 23, wherein
each seat is configured for receiving at least one tray 4. The packaging assembly also includes an upper tool 21 facing
the lower tool 22 and cooperating with this latter to define a packaging chamber 24. The upper tool 21 also preferably
comprises an insert 36 having a respective bottom surface 37 configured in use to contact the film or to stay above the
film; in the embodiment of figure 1, the insert is a film holder having surface 37 which is an active surface for holding
the film sheet or sheets 18 above the respective seats, such that each film sheet 18 may be kept exactly above the
respective tray 4 for then allowing heat bonding of each film sheet to the tray flange 4c of the respective tray. In the
embodiment shown the bottom or active surface 37 is flat, but of course it may alternatively be concave. For the
purpose of holding the bottom or active surface may have suction holes 37a connected to a suction system (not shown)
also controlled by control unit 100.
The apparatus 1 further includes a control unit 100 connected to the packaging assembly 8 and configured for
commanding the packaging assembly 8 to pass from a first operating condition, where said packaging chamber 24 is
open to receive the film, and a second operating condition, where said packaging chamber 24 is closed, optionally
hermetically closed. It is noted that packaging assembly comprises at least one main actuator 33 active on at least one
of said upper and lower tools 21 and 22; the main actuator is controlled by the control unit 100 which is configured for
acting on the main actuator 33 and commanding relative movement of the upper and lower tools along a main direction
(A5 in figure 1), between said first operating condition, where the upper tool 21 is spaced apart from the lower tool 22
and said packaging chamber 24 is open to receive one or more of said films 18, and said second operating condition,
where a closure surface 34 of the upper tool 21 tightly abuts against a closure surface 35 of the lower tool 22 to
hermetically close said packaging chamber 24 with respect to an atmosphere outside the apparatus 1.
The control unit 100 is also connected to the transport assembly 3, to the film supplying assembly 5, to the film cutting
assembly 6, to the transfer device 7 and to the packaging assembly 8 and is configured for activating the transfer
device 7 so as to control motion of the backing structure 16 (or of the upper tool 21, as described above), into the
different operating positions described above. The control unit 100 is configured for synchronizing activation of the
transfer device 7 with passage of the packaging assembly 8 from the first to the second operating condition so that the
movement of the backing structure 16 (at least the portion of movement where the backing structure enters into the
space between the lower and upper tools 21, 22) is caused to take place when the packaging chamber 24 is open
while the packaging chamber 24 is closed only once the backing structure 16 has transferred the cut film sheet 18 to
the upper tool 21 and has been retracted from the packaging chamber 24. The control unit 100 may also be configured
for synchronizing the conveyor 46 such that movement of a prefixed number of trays 4 from a region outside the
packaging chamber 24 to a region inside the packaging chamber 24 is caused to take place when the packaging
chamber 24 is open while the packaging chamber 24 is closed only once said prefixed number of trays 4 is in proper
position relative to the upper tool 21.
Going back to the structure of the packaging assembly 8, it is noted that each of said seats 23 in the lower tool 22
presents a mouth 23b peripherally delimited by an abutment surface 23a: in practice the abutment surface surrounds
the mouth of the respective seat 23 and forms a corresponding radial band designed such that, when the seat 23
receives a respective tray 4, the flange of the tray rests on the radial band formed by the abutment surface 23a. As it
is visible from figures 2-8, the insert 36 in the upper tool 21 is sized to have the bottom surface 37 radially smaller than
the abutment surface 23a and is peripherally surrounded by a heating structure 40 (connected to a heating system not
shown as per se conventional and well known) having a respective heating surface 41 which extends radially outside
with respect to the bottom surface 37 of the insert 36.
In greater detail, the insert 36 and the heating structure 40 are mounted such that the heating surface 41 of the heating
structure 40 surrounds the bottom surface 37 and overlaps the abutment surface 23a of a respective one of the seats
present in the lower tool (at least when the packaging assembly 8 is in said second operating condition): in this way,
the tray flange 4c (or at least an annular portion of the flange 4c) is positioned between the abutment surface 23a and
the heating surface 41. The heating structure 40 and insert 36 may be relatively movable the one with respect to the
other along said main direction A5 such that the heating surface 41 of the heating structure 40 is selectively positionable
at a position where its heating surface 41 does not contact a film held by the insert 36 (see figures 2 to 10), and in a
position (figure 11) where the heating surface 41 contacts the film, in particular a film peripheral band, to cause heat
bonding and tight fixing of the film at least to the tray flange 4c. Note that, several alternative solutions, are possible in
order to achieve the above relative movement: in the non-limitative example shown the insert 36 is connected to the
upper tool 21 such that the vertical position of the bottom surface 37 and that of the closure surface 34 of the upper
tool 21 is the same (i.e. they both lie in use on a same plane, which is normally horizontal) during the cycle: for instance
the two bodies 40 and 21 may be rigidly connected. On the other hand the heating surface 41 is generally retracted
with respect to the active surface 37 and this may be achieved either with an actuator relatively moving the heating
structure with respect to the upper tool, or by having the upper tool with the insert supported by the frame 3 in an elastic
manner such that an upward movement of the lower tool would upwardly move the assembly formed by the upper tool
and the insert thereby causing the heating surface 41 to approach the lower tool.
As to the materials used, the insert 36 may made in an insulating material or it may be at least thermally insulated with
respect to the heating structure to avoid that the bottom surface 37 reaches the same temperature of the heating
surface 41.
In an alternative arrangement, which is not shown in the enclosed drawings, the components 40 and 36 may be in one
single body which may have a bottom surface sized to overlap, optionally completely overlap, the abutment surface
23a of each seat 23 (at least when the packaging assembly 8 is in said second operating condition). In this case the
single body would include one or more heaters configured for heating the entire bottom surface, heating different
portions of the heating surface at different temperatures or only heating a portion of the bottom surface overlapping
the abutment surface 23a.
According to one described aspect, the packaging assembly 8 forms - for each of said seats 23 - a number of first
apertures 90 configured to inject gas towards the respective of said seats; note the same first apertures 90 may also
be used for withdrawing gas. More in detail, as shown in figures 24 and 26-29, the first apertures 90 are positioned in
correspondence of a corner region 23c of the mouth 23b of the respective seat 23: for example one or more first
apertures may be positioned in correspondence of one, two or more corner regions 23c. According to one described
aspect, the first apertures 90 are located and extend above the abutment surface 23a: in other words the fluid passage
area of the first apertures 90 are formed by the terminal edges (92a) of ejectors (92) extending entirely above a first
ideal plane L1 (see for example figure 8) passing through the abutment surface in order to be able, during delivery of
gas into the chamber 24, to eject a gas stream which flows tangentially and parallel to the abutment surface 23b and
therefore tangentially and parallel with respect to the flange 4c resting above the abutment surface so that substantially
no lifting or displacing force is exerted onto the tray 4 which remains always properly positioned in the respective seat.
Again in connection with the position of the first apertures, it may be noted that the bottom surface 37 of the insert 36
lies on a second ideal plane L2 parallel to and vertically spaced apart from the first ideal plane, and that the ejectors
92 and first apertures 90 are positioned and extend between the first and second ideal planes L1 and L2.
Going in further detail, referring again for instance to figure 8, the lower tool 22 hosts a number of first conduits 91
presenting, at one end thereof, terminal edges 92a delimiting the first apertures 90. Note the first conduits 91 may be
made with tubing or more likely be channels obtained inside the body of the lower tool: in any case, the first conduits
are positioned and shaped such as to form said ejectors 92 parallel to the abutment surface 23b and entirely extending
above the same abutment surface 23b; the first apertures 90 are formed by the passage areas delimited by the terminal
edges 92a of said ejectors of said conduits 91 and lie on a surface generally transverse (for instance perpendicular) to
the first and second ideal plane L1 and L2.
According to a further described aspect, each of the seats 23 defined by the lower tool 22 has a respective mouth 23b
of polygonal shape: for instance the mouth or mouths 23b may be rectangular; the first apertures 90 are located in
correspondence of corners of each polygonal mouth 23b. In other words the packaging assembly (and particularly the
second tool) define first apertures which are located in proximity and directly face the corner regions of each mouth of
said seat or seats 23.
In an example at least one first aperture may be provided at a first corner of a mouth and at least one further first
aperture at a second corner of the same mouth (figures 23 and 29) adjacent to the first corner: in particular the apertures
may be located on adjacent corners and be placed symmetrically with respect to a plane of symmetry of the seat mouth
perpendicular to the first ideal plane L1 of the abutment surface 23b. In accordance with the non-limiting embodiment
shown in figures 23-29, the shape of the mouth of each seat is rectangular and thus designed to receive a tray 4 with
a rectangular shape top flange 4c: in this case the first apertures are located at two adjacent corners of the mouth and
may be configured to direct the ejecting flow towards a center zone of the mouth (figure 29). Furthermore, for each
seat 23, a number of second apertures 93 located on a side of the same seat 23 opposite to the first apertures 90, i.e.,
on the side of the seat opposite to the corners where the first apertures are located. Also the second apertures 93 may
be positioned and entirely extend above the abutment surface 23a delimiting the mouth of each respective seat.
Alternatively or in addition, the second apertures may be located below the abutment surface, for instance in
correspondence of the bottom of a recess surrounding the seats 23 (as shown, e.g. in figures 2-10). In the case where
each seat 23 has a substantially rectangular mouth defining first and second opposite sides connected by respective
corner regions 23c, the first apertures may be located at adjacent corner regions while the second apertures may be
located in correspondence of one of said sides opposed to the corner regions where the first apertures are located. As
shown in the drawings of figures 26-29, two or more of said first apertures 90 may be provided at each corner region
23c. In case two or more apertures are present in each corner regions, the apertures are preferably positioned
symmetrically with respect to a plane bisecting the corner and perpendicular to the first ideal plane L1 of the abutment
surface.
The first conduits 91 leading to the first apertures 90 may be channels obtained in the lower tool and present an end,
terminating in said terminal edges 92a and defining said first apertures 90, and an opposite end, in fluid communication
with a gas supply circuit 94, which may include a controlled atmosphere arrangement 30 as further described herein
below. The second apertures 93, on the other hand, are connected to second conduits 95, which may be formed by
channels obtained in the lower tool, having an end, terminating in said second apertures, and an opposite end, in fluid
communication with a gas evacuation circuit 96: the gas evacuation circuit may include a vacuum arrangement as
further disclosed herein below. As shown in the drawings, the second conduits 95 may end with a portion 95a leading
to second apertures above L1 and a second portion leading to second apertures 93 located below plane L1. The gas
supply circuit 94 and the gas evacuation circuit 96 are connected with the control unit 100 which is further configured
to command the supply circuit to supply gas having a controlled composition to the first conduits, and to command the
discharge circuit to withdraw gas from the second conduits. The controlled atmosphere arrangement 30 is part of the
gas supply circuit and is connected to the packaging chamber 24 and configured for injecting a gas stream into said
packaging chamber; the controlled atmosphere arrangement comprises at least one injection device including an
injection pump 31a and/or one injection valve 31b acting on at least one injection pipe 32 connecting the inside of said
chamber, e.g., via said first conduits 91, to the a source of controlled gas (not shown) which may be arranged externally
to the apparatus 1. The control unit 100 may be configured to control opening and closing of the injection valve (or
activation of the injection pump) to inject said stream of controlled gas at least when the packaging assembly 8 is in
said second operating condition, i.e. with said packaging chamber 24 hermetically closed. As mentioned, the apparatus
1 may also comprise a vacuum arrangement 27, part of the gas evacuation circuit 96, connected to the packaging
chamber 24 and configured for removing gas from inside said packaging chamber. The vacuum arrangement
comprises at least one vacuum pump 28 and at least one evacuation pipe 29 connecting the inside of said chamber
24 to the vacuum pump. The control unit 100 controls the vacuum pump 28 to withdraw gas from said packaging
chamber 24 at least when the packaging assembly is in said second operating condition, i.e. with said packaging
chamber hermetically closed.
The control unit 100 may also be configured to control the composition of the modified atmosphere generated inside
the chamber 24. For example, the control unit 100 may regulate the composition of the gas stream injected into the
packaging chamber. The gas mixtures injected into the packaging chamber to generate a modified atmosphere may
vary depending upon the nature of product P. In general, mixtures of a modified atmosphere include a volumetric
quantity of one or more of N , O and CO different from the quantity of these same gases as present in the atmosphere
2 2 2
at 20°C and sea level (1 atmosphere pressure). If product P is a produce such as meat, poultry, fish, cheese, baked
goods, or pasta, the following gas mixtures may be used (quantities are expressed in volume percentages at 20°C, 1
atm of pressure and slight changes around below quantities are in general acceptable):
- Red meat, poultry without skin: O =70%, CO =30% or O =80%, CO =20%
2 2 2 2
- Poultry with skin, cheese, pasta, baked goods: CO =50%, N =50%
- Fish CO =70%, N =30% or CO =40%, N =30%, O %=30
2 2 2 2 2
- Processed meat CO =30%, N =70%
The control unit 100 may be configured to control said injection pump or said injection valve 31 to start injecting said
stream of controlled gas either after a prefixed delay from activation of said vacuum pump 28 or after a prefixed level
of vacuum has been reached inside said packaging chamber 24. In a further described aspect the control unit 100 may
cause the start of the injection of said stream of controlled gas for creating a modified atmosphere while said vacuum
pump 28 is still active so as to shorten the time for creating the modified atmosphere. It is noted, however, that high
oxygen content in the gases evacuated and/or supplied or otherwise processed can entail a substantial risk of explosion
in some of the components (e.g. the pump or pumps). Consequently, suitable components should be used. Moreover,
as it is preferable to avoid having very strong vacuum in the packaging chamber 24 and at the same time it is desirable
to ensure a proper atmosphere inside the chamber it is advantageous stopping the vacuum pump after opening the
gas injection. In this way the pressure inside the packaging chamber can be controlled in order to not decrease below
a desired value. During the simultaneous operation of the vacuum pump 28 and the injection of said stream of controlled
gas, the gas injected is mixed with residual air and the vacuum pump 28 continues to remove the mixture so that the
amount of gas and/or air initially present in the packaging chamber is continually decreased. This flushing of gas and
mixing of the gas and residual air is very important in order to achieve the desired controlled atmosphere in an effective
and efficient manner, while ensuring that the desired pressure (i.e. level of vacuum) is achieved.
According to a further described aspect, it is noted that the control unit 100 is configured to control said injection pump
31 such that the gas flow is not injected at a speed that is too high and that may impair the firm holding of the cut film
by the upper tool. The control unit 100 may control gas injection at a gas pressure set below a limit to prevent
detachment of the film from the upper tool 21 or inaccurate positioning thereof in correspondence of the upper tool 21.
In one example, the injection pressure is maintained between 1.3 and 4.0 bar, or preferably between 1.5 and 3.0 bar.
Note that in the examples shown, the evacuation pipe 29 and the injection pipe 32 communicate with a lower portion
of the packaging chamber which is separated from an upper portion of the packaging chamber. In order to allow proper
circulation of gas within the entire packaging chamber the upper and lower portions of packaging chamber 8 are fluidly
connected by apertures or channels located such as not to be occluded by the tray walls when the tray is positioned in
the seats 23.
Although the apparatus 1 may have one or both the vacuum arrangement 27 and the controlled atmosphere
arrangement 30, it is to be understood that the control unit 100 of the apparatus 1 may also be configured to tightly
engage the film sheets 18 to the trays without activating the vacuum arrangement or the controlled atmosphere
arrangement and thus leaving the normal environment atmosphere within the tray. This may be, for example, the case
for non-perishable products.
In accordance with a further described aspect and in order to generate gas streams of appropriate shape and direction,
the first apertures 90 located at corner regions 23c of the mouth 23b of each seat 23 may have the shape of an
elongated slit having a width w sensibly greater than a height h: in particular the width w of each slit aperture is the
distance between two side ends of each aperture as measured parallel to an horizontal plane and is at least two times
greater than the height of each slit aperture, the height being the distance between the top and the bottom side of each
slit measured parallel to a vertical plane (see figures 27A and 28). Alternatively, the first apertures at each corner region
may be one or more apertures of a shape different from that shown in figure 27A: for instance figure 27B shows corner
regions 23c each having a plurality of first apertures preferably of circular shape and aligned along a horizontal plane.
Note that the contours of the apertures follow the shape of the mouth abutment surface at said corner regions: thus in
cases, as the one shown in the exemplifying figures, where the corner regions of each mouth 23b and of the abutment
surface 23a have a rounded shape, also the aperture contours follow when viewed from above the shape of the corner
regions. As already mentioned the first apertures 90 are located in a specific place relative to the vertical position of
the abutment surface 23a and of the bottom surface 37 of the insert 36. In particular, the abutment surface of each
seat lies on the first ideal plan L1 and the bottom surface 37 of the insert 36 lies on the second ideal plane L2, which
is parallel to and vertically spaced apart from the first ideal plane L1. The terminal edges 92a of the first conduits 91
end between the first and second ideal planes L1 and L2, and thus the first apertures 90 entirely extend in the zone
between the first ideal plane and the second ideal plane; as shown in the drawings the first apertures are slits elongated
in a direction parallel to said first and second ideal planes. Furthermore, the terminal edges 92a of the first conduits
and thus the first apertures 90 are in a position which is radially external with respect to an outer perimeter of said
abutment surface: in other words the apertures are configured to eject gas above the flange 4c, in correspondence of
corner regions 23c of the mouth of each seat 23 and in a location radially external with respect to the radial band
formed by the abutment surface 23a. This allows to having the first apertures in fixed positions with no need of first
conduits of adjustable length and/or position.
In order to facilitate positioning of each tray 4, the lower tool also includes a peripheral formation 97 which protrudes
above the abutment surface 23a (figures 26-29) of each seat and which at least partially surrounds the respective
radial band of each abutment surface 23a. The first apertures 90 are defined in correspondence of corner zones 97c
of the peripheral formation 97, preferably with each aperture extending above the abutment surface 23a at a distance
of at least 1 mm, more at least preferably 2 mm, from the abutment surface. As already discussed, the first conduits
91 terminally lead to the ejectors 92 and said first apertures 90.
In accordance with one embodiment which is shown in figures 26, 27A, 27B and 28, each of the first conduits 91 may
comprise at least an upwardly extending portion (connected to the controlled atmosphere arrangement) and a
connection portion 98 which is located in correspondence of one corner region 23c of a respective mouth 23b; the
connection portion 98 defines an internal channel having a bottom segment 98a fluidly connected to said upwardly
extending portion of a first conduit 91 and a top segment 98b extending transversally to said upwardly extending portion
and terminating into said terminal edges 92a and thereby delimiting one or more of said first apertures 90: in practice
each top segment 98b may form a respective of said ejectors 92. The area of fluid passage of said top segment
progressively increases proceeding towards the one or more first apertures forming a divergent tract which efficiently
slows down the speed of gas injected via the first conduits. In certain cases however it is not excluded that said top
segment presents no divergent tract but rather a constant section or convergent tract.
In accordance with a further described aspect, each connection portion 98 defines, at said corner regions, part of said
peripheral formation 97: in other words each connection portion has a wall 98c directed perpendicular to the abutment
surface which, in correspondence of said corner regions, forms the peripheral formation.
Although the above description referred to a packaging assembly with one seat, in accordance to a variant the
packaging assembly comprises a plurality of said seats: as shown in figure 26 the plurality of seats are arranged one
adjacent to the other (note that although figure 26 shows one row of seats a plurality of rows of seats may be present).
In this variant, the connection portion 98 of one of said first conduits 91 is interposed between two corner regions 23c
of two adjacent seats 23 and forms one or more first apertures 90 facing one of the two adjacent seats and one or
more first apertures 90 facing the other of said two adjacent seats.
As shown in figures 27A, 27B and 28, each connection portion 98 has a top side defining a gripping member 99: for
instance the gripping member includes at least one deformable piece (for instance a piece of rubber or other
elastomeric material) anchored to the top side of the connection portion. The gripping member may be housed in a
recess 101 present on the top side of the connection portion and surrounded (totally or partially) by a flat surface 102
such that a portion of the gripping member emerges from the recess 101 and protrudes above the flat surface 102.
The gripping member 99 of each connection portion 98 is configured to cooperate with a corresponding opposite
gripping surface 103 carried by the upper tool: for instance the gripping surface 103 may be a lower abutment surface
of the upper tool 21 directly facing the flat surface 102 of each connection portion; each gripping member 99 and
corresponding gripping surface 103 - at least when the first and second tools are in the second operating condition -
are configured for engaging a peripheral portion of film 18 held by the insert acting as film holder. In particular, as soon
as the first and second tools reach the second operating condition, the gripping member 99 and the gripping surface
103 clamp a peripheral portion of the film, more precisely clamp a respective corner flap 18c of the peripheral portion
of the film 18 held by the film holder 36. At each gripping surface 103 a plurality of suction holes 103a (figures 23 and
24) may be provided to suck and hold peripheral corner flap 18c of the film: the suction holes are connected to a suction
system 104 (for instance including a respective suction pump) also controlled by the control unit 100 which is configured
for commanding the suction system to suck gas via the suction holes 103a and attract the peripheral portion of film 18
held by insert.
When the tray apparatus 1 is configured for packaging products into trays having a tray flange and tray base of
polygonal shape, then the seats are shaped to have a polygonal mouth 23b and, in an analogous manner, the heating
surface 41 of the heating structure 40 and/or the bottom surface 37 of insert 36, have a substantially polygonal shape
contour as well. In particular in case trays 4 have a rectangular base and flange, then the seats 23 would present a
rectangular mouth 23b and, analogously, the heating surface 41 and/or the bottom surface would have a corresponding
perimeter of rectangular shape. Note that polygonal (or rectangular) also includes shapes where corner regions present
rounded corners. As shown in figures 2-8 and 23, the corner regions of the heating surface and/or of the bottom surface
37 are rounded or in any case fitted such that the corners portions of a film 18 held by the insert or holder 36 protrude
radially outside the heating surface 41 and the bottom surface 37 offering corner flaps which may be clamped by the
gripping member(s) 99 and corresponding gripping surface(s) 103. In this connection, the gripping member(s) and the
corresponding gripping surface(s) at each said corner region 23c operate in a position radially outside said heating
surface or bottom surface perimeter.
Operation of first embodiment
Although the operation of most of the apparatus 1 according to the first embodiment has been briefly discussed, it
should be noted that the control unit 100 governs the overall packaging process executed by the apparatus 1. In
particular, as shown in figures 1 and 2, the control unit 100 is configured for commanding the transport assembly 3 to
displace said trays 4 into packaging chamber 24, for commanding the film cutting assembly 6 to at least transversally
cut the continuous film 10 into discrete film sheets 18, for commanding the transport device 7 to transport the cut film
sheets into the chamber 24 (or alternatively to command the upper tool to pick the cut film sheets as described above).
Once the film sheets are properly positioned inside the packaging chamber 24 above the respective trays 4 (figure 3),
the control unit 100 commands upper tool 21 to hold the cut film sheets (in this case insert 36 is a true film holder and
holding means such as suction holes may be activated) and the transfer device 7 to withdraw the holding plate 16 from
the chamber 24 (figures 4 and 5). Once the holding plate 16 leaves the chamber 24, the control unit 100 causes the
packaging assembly 8 to pass from the first to the second operating condition, thereby closing the chamber 24 (see
figure 8). It should be noted that depending upon the design of the apparatus, the transport assembly 3 may transport
the trays 4 inside the packaging assembly during the above described operation of the transfer device such that
basically the cut film sheets and the respective trays are simultaneously moved into the packaging chamber.
Alternatively, as shown in figures 6 and 7, the control unit 100 may command the tray transport assembly 3 to move
the trays inside the packaging assembly 8 only once the holding plate has left the chamber 24. Upon closure of the
chamber 24, or immediately thereafter, the gripping member 99 and the gripping surface 103 clamp the corner flaps of
the film sheet or sheets 18 hold by film holder 36. In this situation, the film sheet(s) 18 are at a distance from said tray
or trays located in the respective seat(s) as shown in figure 8. Then, with the chamber 24 hermetically closed (in the
sense that the chamber is closed with respect to an atmosphere external to the apparatus 1 and that the only
connections with the chamber are via channels under the apparatus control), the control unit commands controlled
evacuation and controlled injection of gas (see figures 9 and 10). In particular the control unit 100 commands the
vacuum arrangement 27 to withdraw air (figure 9) and/or the controlled atmosphere arrangement 30 to inject a gas or
a gas mixture in the packaging chamber 24 via said first apertures 90, as disclosed herein above (figure 10).
The control unit may be configured for commanding the controlled atmosphere arrangement 30 to inject a stream of
gas after each gripping member and corresponding gripping surface have clamped a film peripheral portion, such that
the film sheet is securely held in proper position.
Gas is injected via first apertures 90 preferably at adjacent corners of a same seat 23 and evacuated via second
apertures at a side of the seat opposite to the first apertures: this allows an efficient filling of the chamber 24 and in
particular of the tray with gas having a controlled atmosphere. Moreover, the gas injection via first apertures is made
forming streams exiting from the first apertures parallel to the abutment surface 23a and directed to a center zone of
each seat: this further improves gas injection without impairing on proper positioning of the film sheet and of the tray.
As shown in figure 11, control unit 100 is also configured for commanding relative movement of the heating surface
with respect to the insert or holder 36 and thus cause the heating surface 41 to contact the film sheet and thereby heat
and bond to the flange 4c a peripheral portion of the film sheet 18: note that during bonding the flange 4c rests on the
abutment surface 23a and therefore the peripheral portion of the film sheet 18 and the flange are trapped and
sandwiched between the heating surface 41 and the abutment surface 23a. The relative movement between the
heating surface and the bottom surface 37, may be obtained by lowering the heating structure or by raising the insert
36 and typically the upper tool 21.
After bonding of the film sheet(s) 18 to the respective tray(s) the control unit 100 commands movement of the packaging
assembly back to the first condition and thus opening of the chamber 24 (see figure 12). The apparatus 1 then expels
the package from the chamber and the cycle above described restarts (figure 13).
Second embodiment of apparatus 1
In FIGs. 14-22 a second embodiment of apparatus 1 is shown. For sake of conciseness only the aspects and
components of this second embodiment differing from those of the first embodiment will be described. Remaining
aspects and components are substantially the same as in the first embodiment and have been identified with same
reference numerals.
The main difference between the second and the first embodiment is the aspect that in the second embodiment the
cutting assembly 6 is located inside the packaging assembly 8 such that the film 10 in the form of a continuous film is
moved inside the packaging assembly and sheets 18 are cut directly inside the packaging assembly. As the cutting
takes place directly within the packaging assembly or packaging chamber, the film sheets 18 need not be transferred
into the packaging assembly or packaging chamber. Thus in the second embodiment there is no need of a component
(such as a moving upper tool capable of picking the cut film sheet or a holding plate 16 with transfer device 7) for
displacing the cut film sheets from outside the packaging chamber to inside the packaging chamber. Rather the cutting
assembly comprises one or more cutting devices 13 with a blade 14 and a blade piston 15 housed in the packaging
chamber 24 and carried by the upper tool. This piston 15 may be replaced by any other kind of electric, pneumatic, or
hydraulic (linear) actuator. The blade piston 15 is mounted to the upper tool and is connected to the cutting device 13
so as to push and pull it in a direction transverse to the film 10, as indicated by the double arrow A2 shown in
and in .
Additionally as the film 10 is not transversally cut before reaching the packaging assembly, the continuous film is driven
with a step by step motion synchronized with opening and closing of chamber 24, e.g. by providing upstream roller(s)
12 or downstream roller(s) 112 with a controlled step-by-step motion governed by control unit 100. Of course other
means for moving continuous film 10 may be envisaged without departing from the scope of the invention: for instance
pincers (not shown) guided along the path of film 10 and acting on the longitudinal sides of the continuous film 10 may
be used.
As a further difference the apparatus 1 according to the second embodiment presents an insert 36 with a concave
holding surface: note that this feature is only exemplifying a possible solution but of course the insert 36 in the apparatus
1 of the second embodiment may also have a flat bottom surface. It should also be noted that, in general, as the film
is continuous there is no need for the insert 36 to act as a film holder as the film is kept in position using holders active
on the continuous film from outside the chamber 24. On the other hand, the insert 36 may act as an insulator in order
to keep a central portion of the area above each tray at a temperature significantly below that of the heating surface
41.
Operation of second embodiment
Operation of the apparatus 1 according to the second embodiment is similar to that of first embodiment. Again, it should
be noted that the control unit 100 governs the overall packaging process executed by the apparatus 1. In particular the
control unit 100 is configured for placing the packaging assembly in the first operating condition. With the chamber 24
open the control unit commands the transport assembly 3 to displace said trays 4 into said packaging chamber 24,
and causes transportation of the film into the chamber 24 such that a film portion is positioned above a number of trays
4 (see figures 14 and 15). Optionally, the control unit 100 may command the upper tool 21 insert 36 (if present) to hold
the film portion to be fixed to a tray. Then the control unit commands the packaging assembly 8 to pass from the first
to the second operating condition (figure 16) and thereby close the chamber 24. Once the chamber 24 is hermetically
closed, the control unit may command controlled evacuation of air and injection of gas. In particular the control unit
commands the vacuum arrangement 27 to withdraw air from chamber 24 (figure 17) and the controlled atmosphere
arrangement 30 to inject a gas or a gas mixture in the packaging chamber 24 via said first apertures 90, as disclosed
in herein above (figure 18). The control unit may be configured for commanding the controlled atmosphere arrangement
30 to inject a stream of gas after each gripping member and corresponding gripping surface have clamped a peripheral
portion of the film portion to be sealed to the tray, such that this film portion is securely held in proper position.
The control unit 100 is also configured for commanding relative movement of the heating surface 41 with respect to
the insert 36 and thus cause the heating surface 41 to contact the film portion of said film to be sealed to the respective
tray. Alternatively the insert 36 and the heating structure may be connected in such a way to vertically move together.
During bonding the flange 4c rests on the abutment surface 23a and thus the flange 4c and the portion of the film to
be sealed to the flange are trapped and sandwiched between the heating surface 41 and the abutment surface 23a
(figure 19). At this point, or slightly before the control unit commands the cutting device 6 and lowers the blade 14 to
the film 10 thereby cutting out a film sheet 18 which is already bond to the respective tray (figure 20). Note that what
matters is the relative movement of the blade with respect to the film so instead of lowering the blade it is alternatively
possibly to vertically raise the lower and upper tools keeping the blade static.
After bonding of the film sheet(s) 18 to the respective tray(s) the control unit 100 commands movement of the packaging
assembly back to the first condition and thus opening of the chamber 24 (see figure 21). The apparatus 1 then expels
the package from the chamber and the cycle above described restarts (figure 22).
Control unit
The apparatus 1 according to the invention makes use of at least one control unit as described above. The control unit
may comprise a respective digital processor (CPU) with memory (or memories), an analog type circuit, or a combination
of one or more digital processing units with one or more analog type circuits. In the above description and in the claims
it is indicated that the control unit may be “configured” or “programmed” to execute certain steps: this may be achieved
in practice by any means which allow configuring or programming the control unit. For instance, in case of a control
unit comprising one or more CPUs and one or more memories, one or more programs may be stored in an appropriate
memory banks connected to the CPU or CPUs; the program or programs contain instructions which, when executed
by the CPU or CPUs, cause the control unit to execute the steps described or claimed in connection with the control
unit. Alternatively, if the control unit is or comprises analog type circuitry, then the circuitry of the control unit may be
designed to include circuitry configured, in use, to process electric signals such as to execute the control unit steps
herein disclosed or claimed.
Comparative Tests
As discussed, the invention allowed to achieve precise positioning of trays in the respective seats and of films, with
minimal, if at all present, issues of tray dislodgment/misplacement, tray flange bending, film dislodgment or film
bending. Moreover, the invention allowed efficient gas injection and gas removal and therefore efficient control of gas
composition inside a package during the packaging process.
To show the effectiveness of the process and apparatus of the invention, the applicant has used the packaging
apparatus of above embodiment 1 with a lower tool configured with 6 seats capable of housing 6 trays each having 15
cm * 20 cm rectangular flange size and a side wall of 3 cm height. More precisely, a first series of tests (test 1 in below
table) has been executed using an apparatus as in embodiment 1, but with ejectors positioned and configured to eject
gas from a position below the ideal plane L1. A second series of tests (tests 2 in below table) has then been executed
with the apparatus of embodiment 1 having ejectors configured as shown in figure 8 to eject gas from a position fully
above ideal plane L1 and with a direction parallel to ideal plane L1. In both cases the gas ejectors were positioned at
the corners of the trays. In both series of tests, 6 trays have first been positioned in the respective 6 seats in the lower
tool. Respective film sheets or film portions have been positioned above the trays and then the upper tool lowered
against the lower tool to form a hermetically sealed packaging chamber. Then vacuum was created until an absolute
pressure of 150 mbar was reached in the packaging chamber. At this point a gas composition was injected into the
packaging chamber (to create the modified atmosphere) via the mentioned ejectors until a pressure of 980 mbar was
reached in the packaging chamber. Finally, the film sheets or film portions were released by the respective film holder
and heat sealed by the heating structure to the top flange of the respective tray forming 6 packages of empty trays.
Then, the 6 trays were extracted from the packaging chamber and a measure of relative residual concentration of O
gas (in mol% = mole percent) was made in each sealed tray by sampling a volume of gas from each sealed tray.
In particular, the relative concentrations in mol % of the gases present in each of the 6 trays for the 7 runs of test 1 with
the apparatus of embodiment 1 modified as indicated above, and the relative concentrations in mol % of the gases
present in each of the 6 trays for the 5 runs of test 2 with the apparatus of embodiment 1 have been made.
Below table recaps the results of the two series of tests:
- test 1 concerns the case of injection using the apparatus of embodiment 1 modified to have gas ejectors
positioned below the level of the tray flange – the test has been executed 7 times (Runs 1 to 7 in below table)
and the concentration of residual O (mol %) gas in each of the six trays/seats and for each of the 7 runs has
been made;
- test 2 concerns the case of injection with gas ejectors described herein positioned above the level of the tray
flange – the test has been executed 5 times (Runs 8 to 12 in below table) and the concentration of residual
O gas (mol %) in each of the five trays and for each of the 5 runs has been made.
Test 1 : injection coming from below flange
Run Seat 1 Seat 2 Seat 3 Seat 4 Seat 5 Seat 6
1 0,048 0,102 0,066 0,038 0,053 0,064
2 0,099 0,077 0,055 0,1 0,11 0,107
3 0,041 0,036 0,054 0,055 0,023 0,027
4 0,258 0,257 0,347 1,35 0,295 0,267
0,216 0,28 0,218 0,23 0,268 0,15
6 0,228 0,286 0,263 0,266 0,385 1,22
7 0,26 0,274 0,254 0,251 0,195 0,26
Test 2: injection over the tray flange according to the invention
Run Seat 1 Seat 2 Seat 3 Seat 4 Seat 5 Seat 6
9 0,014 0,019 0,02 0,008 0,012 0,011
0,012 0,019 0,018 0,017 0,014 0,068
11 0,024 0,018 0,019 0,009 0,009 0,1
12 0,014 0,019 0,018 0,037 0,018 0,246
As it is visible from above tables, in test 2 there has be no dislodgment of the trays, while in test 1 tray dislodgment
has been experienced at least twice (see seat 4, run 4 and seat 6, run 6 in test 1 where the very high content of oxygen
is indicative of tray dislodgment from its proper position); moreover, the invention lead to an appreciably improved
oxygen flushing effect compared to injection of test 1.
Claims (45)
1. An apparatus (1) for packaging a product (P) arranged on a tray (4), 5 said apparatus (1) comprising a packaging assembly (8) configured for tightly fixing a film (10; 18) to one or more trays (4), the packaging assembly (8) including a prefixed number of seats (23) configured for receiving said one or more trays (4), wherein: - each of said seats (23) presents a mouth (23b) peripherally delimited by an abutment surface (23a), each of said seats (23) being configured to receive at least one respective tray (4) with a flange (4c) of each tray (4) 10 resting on the abutment surface (23a) of the respective seat (23), and - the packaging assembly (8) defines – in correspondence of each of said seats (23) - a number of first apertures (90) configured to inject gas towards the inside of the respective seat, wherein each of said first apertures is positioned in correspondence of the mouth (23b) of the respective seat (23) and extends above said abutment surface (23a); 15 wherein the packaging assembly (8) includes, for each of said seats (23), a number of second apertures (93) located on a side of the seat (23) opposite with respect to the first aperture(s) (90); wherein the packaging assembly (8) further comprises: - a lower tool (22) defining the prefixed number of seats (23) and hosting a number of first conduits (91), wherein the first conduits present terminal edges (92) delimiting said first apertures (90) such that each of said first 20 apertures (90) presents at least a major portion extending above the abutment surface (23a) of the respective seat (23); - an upper tool (21) facing the lower tool (22), at least the upper and lower tools (21; 22) cooperating to define a packaging chamber (24); and - a control unit (100) connected to the packaging assembly (8) and configured for commanding the packaging 25 assembly (8) to pass from a first operating condition, where said packaging chamber (24) is open to receive the film (10; 18), and a second operating condition, where said packaging chamber (24) is closed; wherein the lower tool (22) first conduits (91) have an end, terminating in said terminal edges defining said first apertures (90), and an opposite end, in fluid communication with a gas supply circuit (94); wherein the lower tool (22) comprises a number of second conduits (95) having an end, terminating in said second 30 apertures (93), and an opposite end, in fluid communication with a gas evacuation circuit (96), and wherein each of said first apertures (90) is positioned in correspondence of corner regions of the mouth (23b) of the respective seat (23). 35
2. The apparatus of claim 1, wherein first conduits (91) terminally form ejectors (92) positioned and configured to eject a gas stream tangential and parallel to the abutment surface (23b) and therefore tangential and parallel with respect to a tray flange (4c) resting above the abutment surface (23b) of a seat (23).
3. The apparatus of claim 2, wherein the ejectors (92) entirely extend above and parallel to the abutment surface (23b) and present a fluid passage area with axis parallel to the abutment surface (23b) and therefore tangential and 5 parallel with respect to a tray flange (4c) resting above the abutment surface (23b) of a seat (23).
4. The apparatus of claim 2 or 3, wherein the first apertures (90) are formed by the passage areas delimited by the terminal edges (92a) of said ejectors (92) and lie on a surface generally transverse to a first ideal plane (L1) passing through the abutment surface (23b).
5. The apparatus of claim 4, wherein the first apertures (90) are located and entirely extend above the abutment surface (23a). 15
6. The apparatus of any one of the preceding claims, wherein: - the upper tool (21) comprises an insert (36) acting as film holder having a respective bottom surface (37) configured for holding the film (10; 18) above the respective seats.
7. The apparatus of any one of the preceding claims, wherein each seat (23) has the respective mouth (23b) of 20 polygonal shape and wherein said first apertures (90) include at least one first aperture (90) at a first corner region (23c) of the respective mouth and at least one first aperture (90) at a second corner region (23c) adjacent to the first corner region of the same respective mouth (23b).
8. The apparatus of any one of the preceding claims, wherein each seat (23) has the respective mouth (23b) of 25 rectangular shape and wherein said first apertures (90) include at least one first aperture (90) at a first corner region (23c) of the respective mouth and at least one first aperture (90) at a second corner region (23c) adjacent to the first corner region of the same respective mouth (23b) such that the first apertures are located on a same rectilinear side of the respective mouth.
9. The apparatus of claim 1, wherein the gas supply circuit (94) and the gas evacuation circuit (96) are connected with the control unit (100) which is further configured to: - command the supply circuit to supply gas having a controlled composition to the first conduits, - command the evacuation circuit to withdraw gas from the second conduits.
10. The apparatus of any one of the preceding claims, wherein each of said first apertures (90) has the shape of an elongated slit having a width (w) greater than a height (h), wherein the width is measured parallel to an horizontal plane and is at least two times greater than the height, which is measured parallel to a vertical plane, or wherein said first apertures present at each corner region (23c) a plurality of horizontally aligned apertures. 5
11. The apparatus of claim 6, wherein the abutment surface (23a) of each seat (23) lies on a first ideal plan (L1) and wherein the upper tool (21) includes insert (36), with the bottom surface (37) of the insert designed to contact the film developing on a second ideal plane (L2) parallel to the first ideal plane (L1), and wherein the terminal edges (92a) of ejectors (92) of the first conduits (91) position the ejectors (92) and first apertures (90) between the first ideal plane and the second ideal plane.
12. The apparatus of claim 11, wherein the first apertures (90) have a shape elongated in a direction parallel to said first and second ideal planes.
13. The apparatus of any one of the preceding claims, wherein the abutment surface (23a) of each seat (23) 15 extends about the mouth (23b) of the respective seat and forms a corresponding radial band designed for receiving the flange (4c) of each tray, and wherein said first apertures (90) extend in a position which is radially external to an outer perimeter of said radial band, a peripheral formation (97) protruding above the abutment surface (23a) of each seat (23) and at least partially, surrounding the respective radial band, 20 said first apertures (90) being defined in correspondence of corner zones (97c) of the peripheral formation.
14. The apparatus of claim 13, wherein the peripheral formation (97) protruding above the abutment surface (23a) of each seat (23) totally surrounds the respective radial band. 25
15. The apparatus of claim 13 or 14, wherein each first aperture (90) extends above the abutment surface (23a) starting at a distance of at least 1 mm from the abutment surface.
16. The apparatus of any one of claims 13 to 15, wherein each first aperture (90) extends above the abutment surface (23a) starting at a distance of at least 2 mm from the abutment surface.
17. The apparatus of any one of the preceding claims, wherein each seat (23) has a substantially rectangular mouth (23c) defining first and second opposite sides connected by respective corner regions (23c), the first apertures (90) being located at adjacent corner regions (23c) while the second apertures being located in correspondence of one of said sides opposed to the corner regions where the first apertures are located, wherein at each of said adjacent 35 corner regions two or more of said first apertures are provided.
18. The apparatus of any one of the preceding claims, wherein each of said first conduits (91) comprises at least an upwardly extending portion and a connection portion (98) located in correspondence of one corner region (23c) of said seat (23), the terminal connection portion (98) defining an internal channel having a bottom segment (98a) fluidly connected to said upwardly extending portion and a top segment (98b) extending transversally to said upwardly 5 extending portion and forming an ejector (92) terminating into terminal edges (92a) delimiting one or more of said first apertures (90), wherein the area of fluid passage of said top segment progressively increases proceeding towards the one or more first apertures forming a divergent tract.
19. The apparatus of claim 18, wherein the packaging assembly (8) comprises a plurality of said seats (23) the 10 one being adjacently positioned with respect to the other and wherein the connection portion (98) of one of said first conduits (91) is interposed between two corner regions of two adjacent seats (23), the connection portion (98) defining one or more first apertures (90) facing one of the two adjacent seats and one or more first apertures facing the other of said two adjacent seats. 15
20. The apparatus of anyone of the preceding two claims, wherein each connection portion (98) has a top side defining a gripping member (99), wherein the gripping member includes at least one deformable piece anchored to said top side and surrounded by a flat surface.
21. The apparatus of claim 6 and 20 in combination with any one of the other preceding claims, wherein the 20 gripping member (99) of each connection portion (98) is configured to cooperate with a corresponding opposite gripping surface (103) carried by the upper tool of packaging assembly (8), each gripping member (99) and corresponding gripping surface (193) - at least when the packaging assembly (8) is in the second operating condition - being configured for therebetween engaging a peripheral portion of film (10; 18). 25
22. The apparatus of claim 21, wherein each gripping member (99) and corresponding gripping surface (193) - at least when the packaging assembly (8) is in the second operating condition - are configured for therebetween engaging a respective corner flap of the peripheral portion of film (10; 18).
23. The apparatus of claim 21 or 22, wherein each gripping surface (103) is provided with a number, of suction 30 holes (103a) connected to a suction system (104) controlled by the control unit (100), the control unit commanding the suction system to suck gas via the suction holes to attract the peripheral portion of film (10; 18) held by the upper tool (21).
24. The apparatus of claim 23, wherein each gripping surface (103) is provided with a plurality of suction holes 35 (103a).
25. The apparatus according to any one of claims 21 to 24, comprising: a film supply assembly (5) configured to supply a continuous film (10), a film cutting assembly (6) active on the continuous film (10) and configured for cutting discrete film sheets (18) of prefixed length from said continuous film (10) wherein: 5 either the film cutting assembly (6) is located outside said packaging chamber (24) and positioned between the film supply assembly and the packaging assembly, or the film cutting assembly (6) is part of the packaging assembly (8); further wherein the film cutting assembly is configured to cut film sheets of substantially polygonal, shape; yet further wherein at least one gripping member (99) and corresponding gripping surface (103) are provided for each 10 corner region (23c) of the seat mouth and wherein each gripping member (99) and corresponding gripping surface (103) are configured for clamping therebetween a respective peripheral portion or corner flap of said film sheet at least when the packaging assembly is in the second operating condition.
26. The apparatus according to claim 25, wherein the film cutting assembly (6) is part of the packaging assembly 15 (8) and is carried by the upper tool (21).
27. The apparatus according to claim 25 or 26, wherein the film cutting assembly is configured to cut film sheets of substantially rectangular shape. 20
28. The apparatus according to claim 9, in combination with any one of the other preceding claims, further comprising: - a vacuum arrangement (27) connected to the packaging chamber (24) and part of the gas evacuation circuit (96) for removing gas from said packaging chamber (24), said control unit (100) being further configured to control the vacuum arrangement (27) to withdraw gas from said packaging chamber (24) at least when the 25 packaging assembly (8) is in said second operating condition with said packaging chamber (24) hermetically closed.
29. The apparatus according to any one of the preceding claims, further comprising: - a controlled atmosphere arrangement (30) connected to the packaging chamber (24) and part of the gas 30 supply circuit (94) for injecting a stream of gas into said packaging chamber (24), said control unit (100) being further configured to control said controlled atmosphere arrangement (30) to inject said stream of controlled gas at least when the packaging assembly (8) is in said second operating condition with said packaging chamber (24) hermetically closed; wherein the controlled atmosphere arrangement (30) is configured to inject gas into the packaging chamber including a quantity of one or more of N , O and CO which is different from 2 2 2 35 the quantity of these same gases as present in the atmosphere at 20°C and sea level (1 atmosphere pressure).
30. The apparatus according to any one of the preceding claims, wherein the packaging assembly (8) further comprises at least one main actuator (33) active on at least one of said upper and lower tool (21; 22), the main actuator 5 (33) being controlled by the control unit (100), the control unit (100) being configured for acting on the main actuator (33) and commanding relative movement of the upper and lower tool (21; 22), along a main direction (A5), between said first operating condition, where the upper tool (21) is spaced apart from the lower tool (22) and said packaging chamber (24) is open, and said second operating condition, where a closure surface (34) of the upper tool (21) tightly abuts against a closure surface (35) of the lower tool (22) to hermetically close said packaging chamber (24) with 10 respect to an atmosphere outside the apparatus (1).
31. The apparatus of claim 30, further wherein: - either the insert (36) is sized to have an bottom surface (37) radially smaller than the abutment surface (33), wherein the insert (36) is peripherally surrounded by a heating structure (40) having a respective heating 15 surface (41) which extends radially outside with respect to the bottom surface (37) of the insert (36), the insert (36) and the heating structure (40) being configured and mounted for: o the heating surface (41) of the heating structure (40) to overlap the abutment surface (23a) of a respective one of said seats (23), at least when the packaging assembly (8) is in said second operating condition, and 20 o the heating structure (40) and insert (36) to be relatively movable the one with respect to the other along said main direction (A5) such that the heating surface (41) of the heating structure (40) is selectively positionable at a position where its heating surface (41) does not contact a film contacting the insert bottom surface (37), and in a position where the heating surface (41) contacts said film (18); 25 or - the insert (36) bottom surface (37) is sized to overlap the abutment surface (23a) of each seat (23), at least when the packaging assembly (8) is in said second operating condition, the insert including at least one heater configured for heating said bottom surface (37) or at least a portion of said bottom surface overlapping the abutment surface (23).
32. The apparatus of claim 31, further wherein the heating surface (41) of the heating structure (40) and/or the bottom surface (36) of the insert (37), has/have a substantially polygonal, perimeter comprising at least four, corners, wherein the gripping member (99) and corresponding gripping surface (103) at each said corner region (23c) operate 35 in a position radially outside said heating surface perimeter and/or radially outside bottom surface perimeter.
33. The apparatus of claim 32, wherein the heating surface (41) of the heating structure (40) and/or the bottom surface (36) of the insert (37), has/have a rectangular perimeter.
34. The apparatus of claim 32 or 33, wherein the substantially polygonal perimeter comprises at least four rounded 5 corners.
35. The apparatus according to any one of claims 25 to 27 and 29, further comprising a frame (2) carrying: - a transport assembly (3), configured for displacing one or more trays to the packaging assembly, - the packaging assembly (8), 10 - the film supply assembly (5), - the film cutting assembly (6), wherein the control unit (100) is configured for execution of the following cycle: - commanding the transport assembly (3) to displace said trays (4) into said packaging chamber (24); - commanding the film cutting assembly (6) to at least transversally cut the continuous film (10) into 15 discrete film sheets (18), - commanding the upper tool (21) to hold the cut film sheets or a portion of the film above, and at a distance from, said tray (4), - commanding the packaging assembly (8) to pass from the first to the second operating condition, - commanding the controlled atmosphere arrangement (30) to inject a gas or a gas mixture in the 20 packaging chamber (24) via said first apertures (90), - commanding the packaging assembly (8) to tightly fix the film sheet (18) to said support (4).
36. A process of packaging a product (P) arranged on a tray (4) using the apparatus (1) according to any one of the preceding claims, the process comprising the following steps: 25 - moving a film (10; 18) into the packaging chamber (24) of said packaging assembly (8), - moving a tray (4) into the packaging chamber (24) and below said upper tool (21), - causing the packaging assembly (8) to pass from the first to the second operating condition, with the film held above a number of said trays, - injecting gas through said first apertures (90); 30 - heat sealing the film sheet (18) to the tray (4).
37. The process according to claim 36, wherein heat sealing the film sheet (18) to the tray (4) takes place after interrupting injection of gas through said first apertures.
38. The process according to claim 37, wherein cutting of the film (10a) into film sheets (18) takes place outside the packaging chamber (24) and wherein during injection of gas through said first apertures corner flaps of film sheet are clamped between respective gripping members and gripping surfaces. 5
39. The process of any one of claims 36 to 38, wherein the step of injecting gas takes place through first apertures (91) of ejectors (92) and comprises ejecting a gas stream - through said ejectors - tangential and parallel to the abutment surface (23b) of seat (23) and tangential and parallel with respect to a tray flange (4c) resting above said abutment surface (23b) of seat (23). 10
40. The process of claim 39, wherein the first apertures (90) are located and entirely extend above the abutment surface (23a) and wherein the step of injecting comprises ejecting a gas stream through said ejectors which flows entirely above the abutment surface (23b) of seat (23) and above a tray flange (4c) resting on abutment surface (23b) of seat (23). 15
41. The process of any one of preceding claims 36 to 40, wherein a plurality of first apertures (90) is located at adjacent corner regions of a same seat mouth, and wherein the injected gas streams are directed parallel to the abutment surface (23a) and towards a center of the respective seat (23) and then to second apertures (93) located on a side opposite the adjacent corners where the first apertures are placed. 20
42. The process of any one of claims 36 to 41, wherein causing the packaging assembly (8) to pass from the first to the second operating condition comprises hermetically closing the packaging chamber (24), with the film held above a number of said trays.
43. The process of any one of claims 36 to 42, wherein injecting gas through said first apertures (90) comprises 25 injecting a stream of controlled gas for creating a modified atmosphere within the packaging chamber (24).
44. An apparatus of claim 1 substantially as herein described with reference to any example thereof and with or without reference to any one or more of the accompanying figures. 30
45. A process of claim 36 substantially as herein described with reference to any example thereof and with or without reference to any one or more of the accompanying figures.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP15169930.3 | 2015-05-29 | ||
EP15169930 | 2015-05-29 | ||
PCT/EP2016/061211 WO2016193006A1 (en) | 2015-05-29 | 2016-05-19 | Apparatus and process for packaging a product |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ736509A NZ736509A (en) | 2021-02-26 |
NZ736509B2 true NZ736509B2 (en) | 2021-05-27 |
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